The value of backing tracks depends a lot on the type of performance. Someone singing and comping himself on guitar doesn’t need them. The melody and harmony are there (and some percussion if he gets his feet working).
However, if someone is playing guitar instrumentally, as I do, either he’s a guitar virtuoso (which I’m not) or he needs some backup.
Personally I’m not keen on guitar solos. I like to hear the piano, drums and bass in the background. As I play mostly jazz standards, that’s what works best, and the folks I play for prefer instrumentals to a singer as background music. When I play spiritual songs in church, a backing track of guitar and subtle bass works best. I either pre-record the guitar track myself, or if it’s just simple comping I let BIAB do it. I never use a BIAB guitar track that I’m not capable of doing myself.
My audiences in both settings like it very much. No complaints yet! smile

Cheers! -Alastair