I enjoy watching speedruns just because of the enhanced levels of skill & autism it takes to squeeze every last second out. There are a lot of games that I can't imagine wanting to speedrun, but platformers like SMW and Metroid are really good candidates. It's really not a lot different than watching Superplay vids of Cave shooters.

I was watching a Mike Tyson's Punch Out video yesterday that went over every possible permutation of every fight and the odds of having a 'perfect' run that rivaled the best TAS run were something like one in a septillion because of the high levels of RNG in the game. Some of the strats they use to shave time and avoid bad RNG are really smart but wouldn't be optimal outside of a speedrun.

Then again, I'm the guy that will watch Ullillilia play Bubsy for four hours.