We'll, it's not on the list of games, which isn't surprising. I'm torn between the ease and comfort of streaming a game (imagine just taking a Chromecast with you to a hotel or friend's house as a way of transporting your "console") versus actually owning a game DRM free through GOG (thank you paradox for offering games through them!). I would love to see the option through Stadia just because I could then have fewer instances of late game having artifacts (planets on Galaxy view the size of constellation systems) and crashing. Theoretically, you could have even bigger maps with more people playing on them! And with the new/better automation options, you could have massive empires fighting over galactic domination!! It's a pipe dream, but it's still a dream.
And latency isn't that bad. You know the crybabies will use it as an excuse for when their fleets lose: "I told my fleets to retreat, but it took an extra 3 milliseconds and I lost 2 more ships than I should have! Wah!!!" But there are children everywhere, no matter how old they are. And I guarantee there will be less latency through the internet than the lag I have on the only PC I have that is definitely not for gaming.
And with basic Stadia being free next year, it won't be much different than purchasing a steam game. I imagine they'll figure out a way to do mod support eventually, you'll just have to live without mods for awhile if you go through Stadia. Since Stellaris is already supported on Linux it shouldn't be too very difficult to port. However, I'm speaking from a lack of any technical knowledge about games. I could be very very wrong.