If you are playing for dancers there is quite a difference.

Broken ankle being one of them!

Hornpipe stepping relies on the hesitation/dotted note for synchronising. And some polkas don't dance well. I don't think it is Irish polkas - it is more the style of the artist and some smooth any (all) tune out to suit their fingers. And some artists can make virtually any tune into a polka, rant, march, hornpipe and even a waltze.
I just dance or struggle depending on the music quality.