Playing the piano and such like, although beneficial in general, won't land an otherwise insufficiently qualified person a place at a competitive law school or a job at a law firm. Oxford and Cambridge for example, pay no attention to the extra curricular activities of applicants. The academic stuff has to come first.
When my chambers assesses a candidate for pupillage and tenancy we of course hope that the candidate will be a rounded person, but we are mainly interested in their potential to do well as a barrister.