It is to avoid FUD. It ensures no one can derail the conversation into a debate about what constitutes being ‘affixed to a physical medium’.
“But are the tunes really affixed to the medium?”
“Yes, this hard drive in my hand literally contains a bunch of MP3 files” is a lot stronger than: “Yes, in a way, because this tune-generating script technically constitutes a self-extracting archive, your honour.”
> For a work to be “copyrightable,” it must be original and fixed in tangible form, such as a sound recording recorded (affixed to) on a CD or a literary work printed (affixed to) on paper.
is a hard drive not a tangible form? Come to think of it, so is a brain, and everything else capable of storing information. That language is atrocious.
It’s about “permanence”, not being able to copyright a live performance that wasn’t recorded for example. It just means you need to be able to distribute / replay the recording, and that means using one of the current common audio technologies.
“But are the tunes really affixed to the medium?”
“Yes, this hard drive in my hand literally contains a bunch of MP3 files” is a lot stronger than: “Yes, in a way, because this tune-generating script technically constitutes a self-extracting archive, your honour.”