The purpose of conservation in this case is for the public good, else it would be a private collection and hoarded.

To say they are useful for conservation is to say it's for the public, there is afaics no separation of concerns here unless you're arguing the museum should act a private collector in its conservation?

To counterpoint your next argument that the conservation using this material must be handled by specialists, yes it should, if they were casts of bones etc and are themselves genuinely rare and difficult to replicate.

Digital goods are only rare by virtue of the body holding them not making copies... By acting in a private capacity.