"It cannot describe the person, only the material they choose to sing."

Used the way the OP suggests (which is how I tend to use it) it describes the context in which they sing the songs and which shaped their approach to singing.

There's clearly a distinction between the likes of Fred Jordan and Walter Pardon, who sang traditional songs from within the tradition, and revival singers who sing traditional songs. It would be helpful to have accepted and agreed terms to be able to make that distinction without misunderstanding.