English folk songs can work well both accompanied or unaccompanied. In the former case it all depends upon the skill, sensitivity and taste of the accompanist.

In 'recent' historical times such songs seem, generally, to have been sung unaccompanied, for reasons which are unclear (at least to me) but may be related to such factors as rural poverty. What happened in earlier times is anyone's guess - well at least the guesses of those who like to invoke s**ding 'troubadors' at the drop of a hat!