The piano accordian is one of the most versatile of the folk instruments.

Slavic music
Mexican and Norteno music
Some Irish
Balkan
Israeli
Jazz (some really great players around)
Great instrument to accompany folk dancers
Swedish hambos etc.
Norwegian
Some Middle Eastern Music
Polish
Czech
Yiddish and Hebrew

In the hands of a great musician, it becomes a great instrument.

Too much is made of the instrument itself and not enough about the musician who plays it well.

The button accordian (Bayan etc.) is also a wonderful versatile instrument.

Frank