I think the obvious question this raises is what happens when we start embedding someone else's intellectual property or illegal content in the blockchain. Can the blockchain be DMCA'd?
Digital artwork always reduces to an integer, what's the point of buying a number? If you want to give money to the creator, just give money to the creator. Not sure I understand the value of adding a rube goldberg machine to the mix.
The way I understand the appeal is that there is a notion of (virtual) authenticity. It is like paying for the signature. Imagine you own a copy of a painting by Van Gogh, or a painting which cannot be authenticated, then it is suddenly worth a lot less than a painting with a certificate that it is an authentic one and another certificate that you obtained it through legal means.