This is just a discussion I thought of since I see them used interchangeably.

When naming the main category of where you beat the game and do nothing special, do you prefer to call it any% or Beat The Game

Same goes for the 100% equivalent. Do you prefer to call it 100% or All X (All Emeralds, All Tokens, etc)

You should do any% for beating the game. 100% is for unlocking everything in the game, but for unlocking certain things (achievements, quests, etc.) you should use all x (all achievements, all quests)

how i think of it is:

any% for beating the game BUT only IF you can 100% the game

"Beat the game" if there is nothing extra to do/collect that has any meaning

All X to me would indicate that it beats the game while getting/doing All X so it wouldnt be used for 100% (you cant say that "ocarina of time all cows" is the same as "ocarina of time 100%" :D)

then there are cases like sm64 which could technically say 0 star is any% and 120 is 100% but then the naming would be inconsistent when you want the 1 star, 16 star and 70 star categories so it makes sense for them all to be named after the star count.

im not sure but i feel like ive heard or read somewhere that the any% and 100% that most speedrun categories are named come from the old super metroid scene but i could be very wrong, do not take this as a true fact :D