The difference i notice between traditional singers stylistically and some uk revival singers, is the lack of affectation.
I have yet to come across a traditional singer who deliberately sang with a smile on their face all the way through a song.
These ideas were dreamt up and foisted on uk revival singers, by a certain section of the uk folk revival.
To be fair to this group their advice on singing technique to do with warm up vocal exercises, and breath control is very good.