They’re perfect to “turn your group on!” And today’s modern accordions are electric, so you can “let loose piercing lead and swinging chords in audio colors that will flip your audience!” And if you don’t believe them, you can send in the coupon for a recording of “the fab Combo’Cordion Rock/Sound”!
All the cool kids are doing it! Don’t you want to be a cool kid, too?
(Note: if shirts and hair like that are cool, I have photographic evidence of my own coolness from that same era. None of them, sadly, with an accordion.)
[h/t Mitch Wagner, from here]