It's been an act since the beginning with her. It's a carefully cultivated image that helps her win pageants. Kind of like how surprised everyone was the Gomer Pyle could sing. He wasn't that great of a singer, but the contrast between Gomer and his singing was the hook. Same thing with naive Pickler and her "minx" image she has while singing.
Probably true. Personally, I'm not much for people who have to fake something to get something. I'm betting she won't last. Of course, considering the demographics of the show, she could win.....