There is no speedrun in this category in my opinion, it's just getting the highscore. I believe this category should be moved to "miscellaneous" or be straight up deleted

Speedrun.com does have score leaderboards along with speedrun leaderboards (Pac the creator of the website made a form about this before). There's leaderboards with just Score% categories like Swing Copters and 2015 Candy Cup. So score% works fine on the leaderboards here.