Well I think that there is absolutly no border between "Professional" Audio and "Non-Professional" Audio.
Just think about it, today you're using mainly xmms to play some ogg-files, but suddenly you become a little creative, und you want to do some drumming with hydrogen. I see no reason why somebody would screw up his whole configuration just because he suddenly switched from beeing a "consumer" to beeing a "professional". So propably jack is the only way out for the desktop :) -Richard