Basically there are several aspects to a singing performance.

A good singer, technically, can be incredibly boring (like many so called "good" guitarists).

If you're going to see a singer who is an amazing musician, fine, if you're just going to admire technique.

But many (most?) people who go to folk clubs to be entertained by music or a music based folk acts (eg. more patter than music) want a good time. A good spirited performer who's not technically brilliamt will send more people home feeling they've had a good night than the "amazing" but boring..