He wasn't any use in the first place.
I think it is part of a plan. In Bijuu mode, Bee isn't very mobile, so I think they are holding him back for powerful assaults on the Gedo Mazo when there is an opening.
you mad because killer bee> sasuke
Killer Bee is the 8 tails jinchuriki and he watching Tobi summon the ten tails. All he is doing is serving as a launching tool for Kakashi and Guy instead of helping Naruto kick Tobi's ass.
Killer B can't beat him now lmao.