The BC has been verified in the field by Nosler, guys.
As far as why use the AB Vs the SMK....... well without offending anyone. The SMK is not a hunting bullet per Se. It has worked ok and it has been a disaster in hunting from what I have seen. In my opinion not great consistency. That said some swear by it. Personally I will not use it on game. But this is my personal opinion. YMMV.
The accubond is a ballistic tip with thicker jacket and the core is bonded to the jacket. Specifically a hunting bullet. It will not come apart like a cup and core.
The 260 375 accubonds has been used on cape buff without any issues.
Here is a thread. Not too scientific but gives you idea....