Hello! I'm not a CAP main but you can see the movepool creator's reason for the movepool format in their submission:
https://www.smogon.com/forums/threads/cap-prevos-protowatt-movepool.3686823/post-8900857
https://www.smogon.com/forums/threads/cap-prevos-protowatt-movepool.3686823/post-8900857