CyberGene
I am not yet in agreement with your statement "...if she decides to become a pianist and is very good nobody would care how she looks."
Caveat: My view of the piano universe is limited by the facts that I have only been playing/interested for 6 years, I do not attend expensive concerts of the top professionals, and my exposure to the world's top pianists is almost exclusively through YouTube videos.
One thing that has caught my attention has been the physical attractiveness of every, or nearly every female pianist who appears to have a substantial concert touring presence. There are no physically unattractive female pianists with a large public concerts-on-Youtube that I can think of.
On the other hand, there are plenty of overweight, slobbish looking men who have obviously had substantial performance careers as evidenced by their number of YouTube performances in famous concert halls with large audiences. I do not have any greater than normal ability to judge the attractiveness of men. But, I do suspect that many of them would be seen as physically unattractive to female audience members.
So, i have suspected that for women, there is in fact an unspoken requirement of physical "attractiveness" to have any chance at a high level, public performance career. And, it seems there is not a corresponding requirement for male pianists.
Sometimes I attend Steinway Artist concerts at the local Steinway Hall. I think these pianists can be called "professionals", and the female artists are not necessarily physically attractive. I also attend concerts/recitals by "visiting artists" at the local university, and the female pianists are not necessarily physically attractive.
So, my experience suggests that at levels where there are not millions of dollars in the balance, you may be right that "nobody would care how she looks." But, at the top level of piano performance, I see no evidence that physical attractiveness is not a requirement for female pianists.
Like most here, I too enjoy the appearance of a physically beautiful woman. I am perfectly comfortable with this. i enjoy beauty in all its manifestations. Indeed, I continually seek it out. And, my life is richer for it.