>>27117120Yeah, but it's not an Ice-type, and being Electric is actually a pretty good thing. It also has a solid movepool.
Kyurem-B, on the other hand, is a Dragon/Ice type with Electric moves, but it's a physical attacker. None of those types particularly excel in Physical compared to Special. Pair that with Kyurem's awful moveset and you have a pretty underwhelming fusion.
This is why Kyurem-W is so good. Sure, it has the typing problem defensively, and the shitty movepool, but since it's a Special attacker it can utilize the types and moves it has available to it much, much better.