Yes, but the value is not in the token, it's in the art itself. You don't own anything but the NFT itself, not the artwork it refers to. Artwork that goes public domain 50/75 years+ after the artist death anyway (and is way easier to replicate than physical artwork/copies).
As for exchanges. Banks and auctions do not uphold things either, they're the same kind of operators of principles they don't write, they are merely applying the rule of law and use their credentials for that purpose.
As for impersonation, NFTs-as-certificates are of no impact for notable artists, who already have teams and networks that do this work for them (with old or new techs). Easy/manageable/controllable art certificates really have an impact when available first to small and emerging artists (because that's the crucial when and where they do need this kind of foundations and support for their living).