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.