Extremely cool and impressive from a technical and cultural standpoint, is what I think.

Decomps, reverse engineering... extremely tedious and complex work, often maddening.

Also arguably illegal. Not that I... think that it should be, but it could become a problem.

Good for preservation, that alone is golden.

But personally, I don't like to play old 3D games anymore, I stopped enjoying their aged mechanics and graphics. However, retro 2D games... I freaking love them, I could play Sunset Riders until the day I die.

I never got into the old 3d games from PS1/N64 era. After the "novelty" of full 3d wore off, the gameplay was dwarfed by the camera jankyness and slowness of the game. For example the much vaunted ff7 takes at least a minute per random encounter to resolve, assuming you one shot the basic enemies. If you bother with summons or it's a boss, it's not unusual for things to take 10+ minutes, whereas the same kind of battle in ff6, would be resolved in <2min or faster if your menu navigation is fast.

Zelda64/OoT were a bit better, but there was still a lot of fighting the camera which isn't the most compelling gameplay.

That said native PC ports for these games is awesome and I still greatly enjoy Starfox64 and Star Wars: Rogue Squadron, so it would be cool to see what people can do with a recompiled rom for it.