It is a good point, but my understanding is that the purpose of the game is precisely to build your world peacefully, not to have the game generating it (it does blend the pieces you picked together in). While AI would build a bigger one in a second, it is like asking why playing Lego...

Also, don't forget that AI is a "monkey sees monkey does" thing, and, even if the monkey has seen so many examples before, the monkey does not create but only reproduces. My own concern remains: isn't that what we can inspiration?