It is hard to determine ‘what is worth it’ versus what isn’t when it comes to music versus things like academics, school programs versus outside ones and so forth. A lot of high level music students homeschool because being in school those X hours a day, plus the homework load, for them would preclude being able to do the practicing and such they needed, the relative rigidity of being in school didn’t work, other kids do fine with that. From experience, something ends up giving and it really depends on your emphasis. If academics mean more, if the goal is to get into some top elite college, then music might have to slip (at the pre college program my son went to, the kids who were heading towards academic orientation showed by Junior year, their playing tended to tail off). I also wonder about some of the ‘opportunities’ the musically talented kids are given in school music programs, often the real value is to the school music director and the school, not to the kid, but they sell it as being valuable to the child.
One of the things I warn prospective music students about is to avoid the ‘cramming’ idea of practicing, that if you lose practice time during the school year you can ‘make it up’ in the summer and so forth. Playing takes consistent practice, and there is a big difference between practicing 2 hours a day for 7 days a week then ‘cramming’ in the 14 hours over a couple of days, basically cramming doesn’t work well, and my advice would be to find the compromises that allow that consistent practicing. Besides efficacy of cramming, the other thing that is a concern is physical injury, I have seen more than a few kids end up with carpal tunnel syndrome, tendonitis, blown out lips and so forth.