I think women in general are attracted to social relevance; a person who is a social "center" of some kind becomes naturally attractive to them.
If that is true in other areas of power (millionaires, intellectuals, writers, spokesmen, sport figures...), add the fact that women are also very sensitive to the power of music...
I also think they like seeing men doing some kind of focused, premeditated activity, with all their might and decision. When that activity in addition happens to be music, which in the end is something harmless, that you can enjoy without barriers, and dance to... I think all of that is very appealing to them.
(Of course, there's the attraction of money too, I don't know anybody who doesn't like having money, but for example, there are many stories about the Rolling Stones and how the groupies were crazy about them even when they were still very poor).