She is classically trained, but realized at a performance at a small venue that the Lady Gaga persona sold tickets. If you look beyond the costuming and pizazz the music is good and she is a very accomplished singer.
Same with others. Pitbull, who is a pop-rapper, is quite an accomplished singer in his own right. However, he has found that the ‘Pitbull’ persona sells a lot more tickets and song downloads.
Glenn Beck pointed out how well she covered the songs from "The Sound of Music". It's on youtube.