I currently play in a band with 8 other folks and we get paid for playing, we have an offshoot of this group (3 of us) and we get paid a bit less for playing. On odd nights just 'cos I love the music I play in a session in a pub and if the customers stay the landlord will supply a jug or two of ale. I also have a part time day job. Am I pro semi-pro or amatuer? I don't know but a full time pro told me the other day that people like me are killing the folk scene because I sometimes play for nothing!
My own feeling is that If you can make it pay do so if you can't but still love to play and can find a session, join in. The more people hear the music the more they'll come to listen paying or otherwise.
Regards Baz