The player is obviously satisfied that his tuning is spot on for the type of music he is playing. Various musette tunings still have their followers in some parts of the world, and like yourself Im not too keen on the racket thats coming out of that box, which sounds like a two voice MM register with tuning wider than the Danube in a thunderstorm.
To illustrate that big blow your house down accordions are not required to wow the crowds, take a cheap MM Chinese Hohner, replace the reeds, find a kid like the one in this clip, then sit back and listen. Thats a £1500 box with the only apparent modification being a reed upgrade. The tuning is about as wide as most French players opt for these days, unless they play folk or retro musette.
This is a Finnish player with tuning typically found there. IMHO wide tuning wouldnt do at all for that music style, but others would probably disagree.