Hello. Personally for me, Deidara would be better then Kakuzu without BT for some reasons:

1. He does a lot damage.

2. He can be more useful in group and PvP fights because he has a multiple-hit mystery with reset opportunity.

3. He is more ''hard-to-kill'' ninja with his passive (and tanky bonus with spiders, that can be useful vs Ronin team's, etc.).

And last, ART IS AN EXPLOSION!