Bee is also a good teacher on how to use Tail Beast powers. So even if He lost the 8 Tail He has info that can be set to writhing for Future generation of Host ones Naruto long gone.
Both have been useful. It's just in different ways. For the people who says Sakura's been useless. You wouldn't saying healing the entire shinobi alliance which consists of 80,000 shinobi useful?
It depends on what you're looking for. If its medical treatment than sakura. But if just fighting in skills than killa. But if you like naruto you'll only need a medic because you can pretty much handle yourself in that area. But like i said it depends on what you prefer, if you weak than get kill cause he can protect you, and a medic would be useless if the person keeps getting hurt.
Bee. Sakura healed and then got impaled by madara. Oh and she let madara get both his rinnegan. Meanwhile Bee was basically a tag team with naruto since his 9 tails chakra training.