Regarding the article's comparison of the two formats, some context might be that the Fonteneau store is kind of up against the current state of accordion interest in France. Which at the moment is heavily skewed in the bisonoric/diato direction. As with the US, where accordion playing has basically been kept alive by bisonoric Tex-Mex/Norteno players, in France most interest in the accordion is by players of the small bisonorics used in the balfolk scene.
I play both, or that should be "played," as it's been almost 10 years now that I've only picked up my 2-row Irish boxes in passing. I played PA for some time before getting seduced by Irish traditional music and giving about a decade to B/C bisonoric and bisonoric concertina. But ultimately I returned to PA and took up CBA as well. The bisonoric accordions are totally equal to single melody-line folk tunes, and I absolutely get the attraction to the small size and light weight. A small fully-chromatic MM semitone 2-row can be had at around 6 or 7 pounds--that's half the weight of a 26-key PA!
But personally I came to find bisonoric accordions musically and expressively frustrating, and came to feel that if you know the idiom of the folk tradition you're playing in, you can get just as "authentic" a sound of lift and movement from a unisonoric. Bisonoric players will insist that the "push-pull" articulation gives a more "authentic" sound for dance-based folk music, but I think that unisonorics can deliver if the player knows the staccato-versus-legato phrasing of the idiom. Small unisonorics being best IMHO---I feel strongly that the strengths of small PAs and CBAs for folk music are woefully unrecognized and under-emphasized.
I picked up PA much more quickly than B/C accordion, but I'm not a good example because I had 6/7 years of piano as a kid. I did find bisonoric much more difficult to finger and grasp than PA or CBA. I came to hate the limited number of basses, and their bisonoric character made that limitation even more annoying (to me). I did get on like a house on fire with bisononoric concertina, (known as "Anglo" concertina), but on a bisonoric concertina you have several notes that occur both on the push and on the pull, giving many phrasing choices if you learn the Rubik's cube of where they are and how to use one or the other in a phrase at will. Whereas on a two-row bisonoric semitone box there are only two "magic notes" found on both the push and the pull. And I just got tired of it.
