What is the purpose of pops?

[Yourss]

The tile system was not removed at all. Jobs are tiles, pops are tile-plugs. Where you had 25 before, now you have hundreds. It’s still all tiles and tile-plugs

One of the hallmarks of a tile based system is that it has the concept of adjacency. So it matters what you put where. That sort of optimization puzzle is fun and rewarding to people that enjoy those kinds of puzzles, less so to people who view puzzles at impediments to playing the game. Additionally, there is a practical limit to the size of puzzle that each person is capable of solving. Each time you extend the grid, the complexity jumps. You hit a certain point, and everyone is just going to put minimal effort into a planet, then pave over the rest without worrying about it.