The piano has a long history of playing folk type music. I think we all agree that the piano is fine(great!) for blues/boogie-woogie. Bela Bartok used the piano very successfully for Balkan folk tunes - a pentatonic heaven! As an accompanying instrument, the piano is vastly superior to the guitar. Think about that chap (one of the folk clan) who backs Cara Dillon. Great stuff. Think Joni Mitchell! Terrific! I think a lot of folkies have got to "step outside their little square boxes" and explore the piano in all its many settings.