Once again, I'm in the '99 NEC but the requirements here are to be GFCI protected. It doesn't specify as to how to do this. Either a breaker or a receptacle. I prefer to use GFCI receptacles so my customers don't have to wander to the basement or garage to reset a GFCI breaker that trips when they are ready to dry their hair having just stepped out of the shower. That said, it is the choice of the designer.