Norman D, you're right about Susan being put on TV because of her visual image - and its contrast to her vocal skill.   There are no doubt equally gifted singers turned away at Broadway auditions every day.   Vocal talent like Susan's may be 1 in 100,000, even maybe 1 in a million - it's not 1 in a trillion.   
But I think the reason Susan is winning "fans" around the world goes beyond just the plain-Jane-with-the-beautiful-voice thing.   What impresses me most is how genuine and natural and self-accepting she is. I admire and envy her that more than I envy her voice, and I'd wager a lot of more conventionally "beautiful" people around the world are drawn to her for the same reason.

Genie

PS
Mark Bernier, I agree this lady has incredible courage, confidence, grit. Call it whatever you like, except can we please find a less sexist expression to describe a woman with these qualities than "she's got balls?"
*g*