The legal right is not a chain concept and requires the cooperation and enforcement of your local government, and is something anyone can do at any time. And does implicitly and explicitly when they create art. But we're not talking about art when we talk about NFTs, we're talking about certificates of authenticity of art issued by whoever which have no real-world connection.
The provable scarcity is funny, each is unique so each one has a scarcity of 1, but the concept it represents can just be duplicated at will by the issuer or literally anyone else. Say you bought the beeple. Beeple didn't give up the right to sell the exact same thing to someone else, and remains perpetually able to debase your investment at their sole discretion. The scarcity argument holds zero water when compared to for instance Bitcoin, which has a hard-coded quantity. Not that, you know, exchanges can't oversell coins if they wanted to, so long as there's no systemic bank run.
Scarcity notwithstanding, the idea that you can fractionalize, insure and borrow against NFTs in an automated, trustless and decentralized way is pretty weak - to put it mildly. Since each token is unique, there's no consistent bid-ask for you to determine its worth. It's a super duper low liquidity market, and its going to get lower liquidity on a per-NFT basis the more NFTs exist.
All you know is what the last person paid, whenever they paid for it - years ago even. Just because someone at peak mania bought a beeple or whatever for $69 million dollars today doesn't mean you can borrow $10 against it a few years from now. If they tried to resell that NFT today, I can't imagine they'd get more than a few thousand already haha.
That's exactly why art is used for money laundering.
That's exactly why NFTs are used for money laundering.