Part of the confusion and contenion comes from the fact that we're talking about at least two different kinds of "traditional singer."

Literally, anyone who sings "Happy Birthday" in theor own traditional style is a "traditional singer," at least for the moment.

But the "traditional singers" we're interested in are a subset, who may be defined as "traditional singers *of interest to fans and/or students of traditional songs."

Such singers may be "interesting" for any of a number of reasons and to various sorts of interested fans and/or students: large traditional repertoire, one or two rare traditional songs, striking texts, songs learned under colorful circumstances (under sail, for example), truly archaic style, great voice, affecting performance, etc.

Then there are the rest of us. It's the "interesting" singers of traditional songs (and players of traditional music) we're interested in.