higher ram apple silicon should be able to run it too. if they don't use some ancient pytorch version or something.

Why not on a CPU with 32 or 64 GB of RAM?

Much slower memory and limited parallelism. Gpu ÷- 8k pr more cuda cores vs +-16 on regular cpu. Less mem swapping between operations. Gpu much much faster.

Performance, mostly. It'll work but image generation is shitty to do slowly compared to text inference.