> Heck you can probably import it directly from Unity's asset store without even bothering with Stable Diffusion.

Try actually doing this though and it'll look like an absolute mess. You'll end up without any sort of cohesive art style and you'll have random variations in quality level. The thing about this AI generated stuff is that what it lacks in 'peak talent' it more than makes up for it in being able to actually produce something cohesive.