jim ,is right it is important to encourage people to perform and improve their performances,
but selecting singers on the basis of what they sing is something different, personally i do not want to hear buddy holly songs, however the last person i heard do them was Andy Caven, who was a practised competent good performer.
I booked him at the folk club i ran because the audience asked for him, i also booked nic jones john and julia clifford steve turnerjohn and sue kirkpatrick, the club did not have a massive fall off in attendance because i once booked andy caven