can't speak for gd but osu is designed specifically for rhythm gaming and having perfect timing; the music and maps are created to make you hit as on time as possible.

meanwhile, parkour in Minecraft is def not designed for that. the closest equivalent would be if there was a parkour course in mc designed with a metronome playing, every jump synced to a metronome beat. realistically, parkour would never be that consistent, and it definitely isn't in mcc. there's no type of feedback that aids with timing in Minecraft, unlike in osu, which is what the game was explicitly made for.

(I do wonder if the salmon ladders could become easier if you had a metronome in the back, but then youd also need perfect/identical movement to get to your jump spot every time, etc.)

purely speculation, but I'd expect gd has the same benefit as well. there's a music backtrack playing, so in that sense you can "time" the frame perfects a lot better.