good to have some healthy debate! Yoou are quite right torctgyd the continental is totally logical, probably easier to find and possibly easier to sell, it is however really a very close relative of the piano accordion which some would argue that we should all be playing!
The British button box is quite definately a part of the push/pull melodeon family and as such would , perhaps if better understood, have more appeal to us mere melodion players. It could be that many DG players have been put off by the BC and its 2 row relatives which all have fairly useless bass when it comes to driving a rhythm. the bcc# with accordion bass gets round this problem completely.The other major turn off is the lack of any sort of tutor book (james hanrahans 'the box' bc tutor will just about get you started but not much else. Also there are not many people aro;;und who give tuition on the 3 row.
It is perhaps surprising how enthusiastic newcomers can become - at the moment I am teaching 2 people the 3 row and am attempting to write a tutor which will probably be printed in small batches as & when needed. One of the problems is the sort of myth surrounding the instrument bro;ught about to some degree to not being able to follow just what a player is doing by watching him. as against watching a piano accordion players who obviously goes up for up & down for down.

The main snag is that , like most i;nstru;;ments it needs to be properly learned ;& to do this in a reasonable time some sort of external input is helpful but not easy to find. To this end Jo;;hn Kirkpatrick & myself are trying to put together a list of players & those interested in taking up the system so that some mutual support can be given & perhaps the odd! gathering arranged. Anybody wishing to be included let me know by personal message.

Incidentally I also play a dg which is ideal for morris due to its light weight portability and rhythmic drive. the 3 row on the other hand is a fascinating experience & well worth the effort

cheers
bb