At the beginning of the movie 'Songcatcher', there is a beautiful rendition of 'Barbara Allen' accompanied only by piano. It's in the traditional arrangement and quite moving. I play guitar and mandolin and can make some chords and other sounds on the piano (I really can't play). From my perspective, because I can't play the piano like I can the guitar, I admire a well-played tune on the piano. Also, playing accompaniment is more difficult than just playing a melody from sheet music. Most folk and bluegrass musicians cannot play the piano, but it is a gift just as playing the guitar is.