>>535762869
lucy's M6 makes it rain down boars while piper is spinning (and after that they start spinning themselves)
but outside of M6, i don't think it's a big damage increase (slingshots and the like)

>>532619062
some agent's M6s give nice new abilities, like lucy's (especially if paired with piper)
the rolls are worth more since they have a chance for S / bring you closer to pity, but if you really really like the A agent and intent to use them, then go for it. alternatively i think they can give you agents you don't have for completionism, but not sure if it's dupes only
you definitely don't need the S balls

It's recommended to Max Lucy's Basic Attack skill because her boars use this skill, and they are prmanently helping you in the background.