Well let's be honest, I don't think Apple is going to release a buggy POS security feature that they are calling the future with Face ID. It might need improvements as time proceeds forward, but this company values and releases technology they have complete faith in. That's What makes Apple so great in so many different respects, they have reliable software.
Buggy maybe. But, there are a lot of unknowns and questions we will likely have to await launch.