I disagree that there isn't already generative music that is enjoyed just for its aesthetic qualities. I'm a huge fan of Brian Eno's work, which is highly generative (and he's even published apps that will simply generate ambient music for you 24/7).
"Since I have always preferred making plans to executing them, I have gravitated towards situations and systems that, once set into operation, could create music with little or no intervention on my part. That is to say, I tend towards the roles of planner and programmer, and then become an audience to the results" - Brian Eno
I think generative music is particularly effective as ambient background or as part of a larger art installation. Also, if you're working on developing new synthesizers I'd highly recommend you get to know Eno's work.
"Since I have always preferred making plans to executing them, I have gravitated towards situations and systems that, once set into operation, could create music with little or no intervention on my part. That is to say, I tend towards the roles of planner and programmer, and then become an audience to the results" - Brian Eno
I think generative music is particularly effective as ambient background or as part of a larger art installation. Also, if you're working on developing new synthesizers I'd highly recommend you get to know Eno's work.