If you had been around when Matt was alive, apparently he was an accompanist's nightmare (no, he didn't play himself but got others to accompany some of his songs). He would start in one key, so they'd just worked out what chords to use, then he'd stop and make a comment or tell a joke, and resume same song, but in a different key, so you either had to know lots of chords, or be very slick with the capo!