"a frame is a frame" - of course it isn't that makes no sense. The point of high frame rate is to have more frames that render the game state accurately for more subdivisions

Otherwise you could just duplicate every frame 100 times and run at 10k fps

Or hell just generate a million black frames every second, a frames a frame right

Latency and visual artifacts.

let me just apply my super proprietary machine learning architecture... ah yes it's done, behold, I can generate 3.69 trillion frames per second, because I compressed each frame to a single bit and that's how fast the CPU's memory bus is

the main point of more fps is lower latency. if you're getting 1000 fps but they are all ai generated from a single real frame per second, your latency will be 500ms and the experience will suck