zlacker

If, as a human artist, I decide to train myself on the discography of a famous artist, then produce songs in his style and sell them for cheap so that others don't have to pay for the original artist, then I am sure it is fair use. It is done all the time.

Now, what if instead of training myself using real instruments, I train my AI and do the same. Is it different?

It is complicated, but there are many arguments in favor of fair use, probably more than they are against but as you say, let's the courts decide.

But in any case, piracy is illegal in every case. As a human, it is illegal for me to use pirate copies, whether it is for training myself as a musician, for training my AI, or for simply listening.