Although I haven't yet done so, I would use BL to collaborate privately with known people. It does allow projects to be private to your own "band".
Specifically I'm thinking of my nieces and nephews who although musical do not yet have experience of recording and live too far away for me to demonstrate. But they can use their smartphones and I'm sure will learn BL a lot quicker than learning CbB.
Btw the phone app appears to have a 5 minutes recording limit.
Wei Liang