Why do you need an expert to vet something when you buy it from the artist that made it? And in turn, when the artist put a piece on a blockchain you can trace

Why do you need an expert to vet something when you buy it from the artist that made it? And in turn, when the artist put a piece on a blockchain you can trace it back to the artist. That's the point of NFTs kind of. But if you mean you'd rather have a physical original of an artwork than a digital representation of the thing, I see what you mean I guess.