Except there's no guarantee of authenticity. Up to 80% of all artwork being sold is copied. Frequently people will sell exactly the same thing as "unique" multiple times. Yes, supposedly the certificate itself can't be forged but you aren't buying anything "real" in any sense that couldn't be replicated with less power-hungry options.Think of it like a digital certificate of authenticity, for a digital resource, with a fair amount of tech complexity behind it to try to ensure that other people can't forge a copy of your certificate.
If anyone is interested, there's a more in-depth article here.