The range will be reduced compared to English concertinas and the big bionic brothers, but at 21/2 octaves, give a few notes more for some keys, the little instrument will have a fair range, better than the smaller (48 bass) piano accordions many play in sessions for ease and being unobtrusive, and not far behind the full size accordions, F3 - A6, which is only three octaves and a major third. It will be better than chromatic harmonicas, better than melodeons, approximating a whistle: so not too bad
Comparing the instrument with PAs big or small may be adequate re playing in sessions asf. where no harmony is needed (or tolerated). Apart from that you would have to include the "left side" in the comparison, wouldn't you?
So I guess, for playing "single line melodies" the range wouldn't be too small at all, but otherwise the instrument might have to be considered as in a way restricted - however it's just like with all restrictions: they're a challenge as well, and can be met as that...
So, apart from the vibrato, of course you should go for it, and I wish you the best of luck with that!
Best regards - Wolf