Its not though, the signature and the digital art are stored separately. Their association only exists within a controlled a system. So that, you don't actually have a signature attached to art, you have a signature associated with art, and only when viewed through a website such as OpenSea. You're not investing in the infallibility of math. Your "investing" in some joker with an httpd server, who pointed two records at each-other in a database, the same way any other database works. Imagine someone giving you a number, and saying somewhere there's some art that this number means you own. You can check to see what art you own, only by plugging your number into my software... that's what you've purchased.