But all of these impulses are pretty much in line with the roots of rock and roll. It has nothing to do with being credible, although with some it might be a confidence builder to help show remind themselves that they aren't simply one of the "drones" who work in an office. Maybe it says something about them that they need that reminder, but it doesn't invalidate it.
I have a lot of "rock memories" which aren't based on being scared, shocked or intimidated. But frankly I also have plenty which DO have to do with that. It's a long tradition, and not necessarily a bad one, to have your foundations shook up a bit. And women aren't "supposed to be" "intimidating" or "different" in our culture. Ergo, it could be kind of a good move for her to play that card (although she seems very personable when NOT singing, and that probably helps too).