So, if steamsounds is a hobby(!), why do I have a shop?
When I first started I used free web hosting. Remember Tripod? As time went by, steamsounds web grew and so did visitor numbers. More visitors meant more bandwidth and, quite soon, free web hosts were no longer up to the job.
Bandwidth requirements have continued to grow and reliable hosting isn't cheap so selling a few CDs helps to offset the cost of hosting two domains and means that I can keep steamsounds going!
As for steamsounds being a hobby; sometimes it seems more like a full time job but as long as I and my visitors enjoy it (and it doesn't cost me too much) I'll keep it going!