What would we talk about in the banjo uke forum that has zero relevance to other types of ukuleles? We'd have one thread about where to put the moveable bridge. One more thread about tensioning the head. And then... ?
I guess some people think of banjo ukes as entirely different instruments. I think of them as ukes. IMHO the vast majority of threads on UU are equally interesting no matter what kinds of ukes we're playing. Songs, chords, strings, how to practice, how to gig... it's all part of the same conversation. I wouldn't make separate forums for sopranos, concerts, tenors, baris, resonators, electrics, plastic ukes... nor banjo ukes.
But that's just my opinion, and I admit to having a habitual bias against splitting forums up into ever smaller enclaves. I am interested to read what others say. How many of you play banjo uke and not any other kind of uke? How many of you would prefer to discuss banjo ukes with other banjo uke players and not waste your time scanning posts about ukuleles in general?