They boost your might stat when summoned by about 246 might, sorry not in game so going by memory. They also all have unique abilities in combat and they attack enemies with you. In addition to attacking Baby Boo and Boo Junior will shield you in combat, it graphically looks like a mental shield. If you have the Bootility Belt you can summon all 4 boos at once (if you have them) and it's like having all four out at once attacking, Does some decent damage, but having the bootility belt on full time may compromise your overall stats a little, can be usefult to have an armory set up for it so you can switch between that and a regular set up after summoning them. It really depends on what the content is you're running and whether they're going to be worthwhile using in any given circumstance.
in stat clamped events, the loss in stats for the belt is not a thing. i would say: the best use of the bootility belt with the whole family would be in event contend, using alts who do not have the marks to unlock and allways have your base generator trinkets activated.
Seems like having a armory with 3 x Boo while keeping up cr with regular dps trinket would be a good option. Depending ofc armory cooldown. Which i dont remember atm.
