Do you really think people are so stupid as to believe you have somehow "pranked" Verisart? The certificate you created clearly lists YOU as the artist. Do you understand what the word "provenance" means? It means "place of origin". Does anyone really care the title or even image of an art piece? Is that where the value is derived? Or is it the ORIGIN of the piece that matters? Who cares that YOU have claimed to create a piece of art. Who are you? A famous artist? No. Any art work you create would be worthless because you have no artistic talent. So who cares what YOU have registered on the blockchain. Trust me... no one cares and no one will ever care.
If you want to "prank" Verisart then why not register a piece under the name of a famous living artist like Hirst? Do that and you have "pranked" Verisart. But until then... you have done nothing more than disparage an idea with an idiotic argument that only very stupid people may agree with.
Regarding your "switch out the piece" argument. Of course this is possible. Yet another genius observation by you. But so what? Is that the problem in the art world? That rich people are criminals? Really? You think it is rich art collectors who are going to "switch out" an art piece so there is a fake in the world? Seriously? You really think that is the main problem with fakes in the art market? Or maybe it is criminals who create fakes without any legitimate claim to the original? Do you think?
Do you know what a digital certificate of authenticity is? It is simply an infinitely better improvement over a paper certificate. Why? Because a digital certificate cannot be forged whereas a paper certificate can be. Do you understand the value of that? Do you understand this is possible only with an immutable blockchain-based database?
Do the world a favor. Try to think a little before you start blogging about topics you don't understand.