I play many instruments of vary different types - unfortunately none of them to the standard I would like, and none of them as often as I would like.

I think you are trying to largely compare 'apples & oranges'...

I do go along with the different playability of different instruments, especially for the 'relatively inexperienced'.

However I will say that I once saw a guy play a large repertoire of tunes that one would normally expect to be played on a piano accordion, but he played them flawlessly on a button accordion - and if you closed your eyes you most likely could not tell the difference, except for the subtly different tone difference between the two instruments.

I mean, no inhibitions caused by having to reverse bellows or cross rows for the tunes - he just WAS that good... better than many piano accordion players, and definitely MUCH better than MOST 'button accordionists' I have seen. I'm not talking 'speed(velocity)' - but he could play pretty quick too...