" Tennis is basically an individual sport, and unless you are USTA very highly ranked, I wouldn’t think it’s worth much in college admissions. (I hope I am wrong because my kid plays varsity tennis, but nowhere near the recruitable level, so sadly I think I am right.)"
A girl does not need to be USTA very highly ranked to get college admission benefits. Having 1-2 recruiting stars ( that is really not that high a level) may help with admissions to the colleges like Bates, Hamilton, Connecticut College, Colby, Brandeis, NYU, URochester, CWRU, Wellesley, MHC, Haverford and many others. If she gets to 3 stars around the end of junior year then the circle will expand to include CMU, MIT, WUSTL, JHU, etc. Not a bad list.
If she is not going to be a recruited athlete, then it doesn’t matter. I would have her do both until she prefers one. Or back off tennis to be weekly lessons.
I would look for which one would provide leadership opportunities…like can she help teach dancing when she gets older to the little ones?