Given how hive-minds work, expansion is actually slower expansion. Expansion is better as a second tradition, if ever.
Hivemind colony ships are gated in the early game more by food than alloys. Gestalts have greater alloy potential than normal organics, since they don't need consumer goods, but for hive minds it's heavily offset by food, with 500 vs 200 food requirements. You need more drones, working more time, to get the food to afford a colony ship, which is why AI gestalts are usually so delayed in getting colony ships started. Expansion doesn't help that, and actually complicates it since the first job a second pop plays after the food-hungry spawning pool is the also-food hungry coordinator drone (to offset the admin cap of having the planet. Those two pops have a -7 food job upkeep- not including the pop upkeep- or one farmer on your homeworld.
+4 starbases with hydroponics bays blows the food limit out of the water. +40 food a month nearly pays for a colony ship's food per year, whereas it'd take over 6 homeworld farmer drones to match that output... which would be two districts in mineral cost (the biggest early-game chokepoint) and 6 pops (in an empire that has maybe 30-ish), pops not working science or alloys instead. This is even more significant with Tree of Life, which has an even higher food cost.
The colony development speed is marginal, going from 2 years and 10 months (58 months) to- with a 25% boost- about 46 months, or a 12 months savings. Better than nothing, but if a year's worth of colony ship food a year lets you settle a year early, it negates. If it lets you afford the colony ship two or more years early, it's not only far superior, but even offsets the 10% growth rate. 10% growth is- early on- worth .3 growth a month, or +3.6 growth a year. Getting a colony set up a year earlier with base growth is worth 3 growth a month, or +36 growth. You'd need a decade for the 10% growth to match the benefit of each year Unyielding helps you settle earlier... and that's if you don't just take the 10% growth tradition before then anyway as a second tree.
And this is without mathing in the implication of hive pop assembly. For most empires, growth is most decisive early game because of how long it takes for pop-assembly to come on line. But pop assembly is immediate as soon as the first pop for gestalts, so the marginal impact for total planetary growth is something like half that for hive minds. (3.3 is a 10% growth, but 3.3 + 2 , or 5.3, is only 6% growth- which itself will be caught up if you take the Expansion tradition second, well before most planets are acruing much natural growth.)
Considering your Hive mind's unity potential from coordiantor drones, if you go Unyielding first that's basically what happens.
The 100 alloys per upgrade amounts to about 300 alloys for the first three starbases you'd normally get (once you have enough stations to build to 4 starbases rather than the starting 3), and at that point of the game the 300 alloys are what would enable you to get 6 starbase modules up as soon as you can. The hydroponics bays are actually more useful than the solar panels, as they have a higher effective job output (10 to 6 vs 6 to 6), and let you basically immediately transfer all your homeworld farmer drones to othe drones, which likely increases your science and alloys more than if you freed up the generators.
Nah, Catalytic Converter is busted in the early-game with unyielding. It's basically worker-free alloy upkeep.
Most analysis on Catalytic vs non-catalytic focuses on later-game productivity ratios per pop of farmers vs miners when the tech upgrades come into play, but that misses the economic advantage that matters more- early game pop utilization.
In gestalt or normal empires, the biggest early-game chokepoint of the starting decade- the factor that prevents you from being able to maximize scientists and alloys- is minerals more than anything else. Your starting mineral income is low, and you need hundreds of minerals to building anything. Meanwhile, both scientists and alloy workers are very hungry in mineral upkeep (either directly with gestalts, or to fund alloy/CG production as normals), with the worse effect that they lower your mineral income at the point of the game where any income lowering also delays your building investments by months or years. When every industrial district or science lab build directly or indirectly lowers your mineral income by 12- the cost of upkeep for the alloy/CG production to support it- that can slow your economic rollout by months or years.
Catalytic converter is great because it offload your starting-game alloy upkeep to a source that doesn't require workers, thus leaving more minerals to fund your science game. Even at 9-food-a-converter, 4 starbases with 4 hydroponic bays can cover the upkeep of 4 catalytic converters on your capital, for a very healthy early game +12 alloys. As empires usually start at +12 alloys, that's basically an early-game doubling of your alloy production economy without needing a single worker playing upkeep. With Unyielding, 8 starbases can cover the cost of 8 alloy workers for +24 alloys. Hydroponics-cataltyic starbases pays themselves off in about a decade, and then gives excess alloys (compared to what you'd otherwise have) every decade therafter.
This is in addition to shifting your early game war-science economy. As you need far less minerals to support an alloy economy, you can focus on early-game corvette boosting techs rather than mineral economy techs as your starting picks. And because your alloy upkeep is food, society research- not engineering or physics- becomes the basis for improving your alloy upkeep economy. Meaning, again, that you're freer to prioritize engineering onto war rather than alloy-supporting economics.
Combined, this gives you a starting economy that can afford both fleets without needing to increase the worker upkeep base per district, and use those saved workers as science for a science boost, and enjoys greater tech pathing efficiency letting them bee-line to corvette techs.
All together, catalytic-gestalts can pretty reliably crush enemies by year 25, as your starbase hydroponics bays finish paying themselves off and start funding an overwhelming alloy economy for corvettes who have had time to get multiple early military techs from the scientists afforded by not having to pay the alloy upkeep in miner-pops. Those conquests, in turn, become the basis of your snowball, whether the pops are conventional conquests or hive-mind livestock (at which point they become part of the gameplay loop, as captured livestock provide the food to expand alloy production for more fleets to capture more food).
(Because empires are generally still relatively equivalent at this point, this will often be more about rivalry wars... which means a chance to get several hundred influence for the resource edicts which you otherwise wouldn't be able to afford, giving you even more worker efficiency to afford more scientists and alloys...)
All this is missed by the usual 'well, fifty-sixty years in, with all the economy techs, miners are marginally more efficient per pop than catalytic converters.' That's missing the forest for a tree. Catalytic plays it's gameplay role in the first 30-odd years, and it's a war-economy civic that lets you start your snow-ball far faster than a typical bloom strategy.
