To be honest I never found these things to be anything more than a curiosity. I'm yet to see a system that produces music that I would call "good".
This is really in the eye of the beholder. One man's trash is another man's treasure.
There's plenty of incredibly popular music created by humans that I absolutely detest, compared to which computer-generated music (as boring, random, or predictable as it might be) can't possibly be any worse.
For my own personal taste, it's rare that completely computer-generated music sounds "good" to me, but it happens. Here's an example, from one of David Cope's EMI (Experiments in Musical Intelligence): [1]
When we depart from strictly and completely computer-generated music to music that contains some generative elements which are "curated" or guided by humans, to my taste the music gets much better. Then we get in to the realm of what could be termed human-computer collaboration.
I like Brian Eno's analogy of "composer as gardener", in which the composer may plant musical seeds and then guide the music to fruition, while not controlling or being the "author" of every nuance as happens with more traditional views of composition.[2]
[1] - ftp://arts.ucsc.edu/pub/cope/beet2.mp3
[2] - https://www.edge.org/conversation/brian_eno-composers-as-gar...
In fact algorithmic music is exactly what it appears to be - the design of relatively trivial mechanistic automata that generate notes and/or sound.
[1] Yes, genetic algos have been used in algorithimc music. No, they haven’t been any more succesful aesthetically than other approaches - possibly because all algo approaches seem to have a simplistic view of the domain, and if you’re stuck in that local minimum it doesn’t matter which algos you use.