"I tell people that 'the button accordion was the Casio keyboard
of the late 1800's.' "

I'll go along with that, and with much of your argument, especially portability, 'much less to go wrong', and 1st use by 'untrained musicians'; the bulk of trained musos at certain times in history were 'keyboard trained'. Also piano accordions, from what Bob Bolton intimated to me, were far more expensive, thus also economically and culturally restricting their market. Also, you could get a 'usable-muso' capability (with either button or piano box) much faster than with a violin, etc.


"It tends to put the player in the key intended by the makers and coordination of the left and right hands is nearly automatic, once one figures things out."

Yes - But I have never been able to be comfortable on a harmonica, the lack of 'all the notes' is the reason. And as for the chromatic, that's even harder for me...


"I think the piano accordion is initially 'easier' for a 'trained
musician''

It's 'dead easy' for a keyboard player, and the more music theory you have on chords, scales, etc, the easier the Stradella system (one of two technical difference from a piano!) is to pick up.

If you have any pipe organ (or wind pedal organ) experience, the free reed accordion is VERY similar, and VERY different to a piano, so the bellows concepts (the other technical difference) have mostly been covered, you just need the ability to physically control it (which is also muscular training!).


'but for traditional or folk music any initial advantage disappears once a rather quick understanding of the diatonic system is impressed into the neurons."

For some people.

"The piano accordion appeals intellectually; viscerally, buttons perhaps work better."

For some people.


"120-bass piano accordion and managing all of that weight and size"

Which is why I have several instruments - I play more of the 'fast and interesting rhythm' stuff on the 'baby boxes' - you don't need 120 bass buttons for much music (bass major, and sometimes minor will cover most 'folk & popular music') it merely gives you an 'any key versatile' instrument in one box, instead of several.


One of the other points of 'buttons vs keyboard' - once you have 'all the notes' laid out and playable in both directions (any other setup would be 'illogical' with a keyboard!), you sense a NEED for the bass side to do the same.


"Even for someone trained on piano, the size of the keys makes for fingering anomalies. "

My boxes have about 4 different sizes of piano accordion keyboard spacings (the miniatures, while being lighter, do have this drawback) - this has never worried me, as many 'electronic keyboards', especially cheapies, are of different key sizes - I just need to keep a vague visual contact with the keyboard when changing instruments to avoid such hassles.