Linus Akesson (big in the C64 demoscene) created the only good example of an NFT I've come across [1]. In the token he puts the source code to his "A Mind Is Born Demo" which compiles to the very demo you watch when you view the token [2].
Nothing really. He addresses this in his post. But also the purpose isn't to sell the song (it's already creative commons). Purely just a commemorative token (and the only one he plans to make. It's not about ownership of the song though.
But the reason why this is such a great example for me is because the token actually contains something substantial. This song is now permanently a part of the blockchain, as opposed to just some link to an image host that might not exist in a decade.
[1] http://www.linusakesson.net/scene/a-mind-is-born/nft.php [2] https://opensea.io/assets/0xa7702e0769c5d408ebf2b056d7c3cc0a...