I agree 100%. There are much better options for digitizing and managing collections information, such as creating or joining one of the Symbiota portals. Though centered on North American herbaria, Symbiota is not geographically or taxonomically limited.
One should also consider issues of data ownership. An individual not associated with the museum or herbarium should probably not take it upon themselves to add an iNaturalist observation for one of their specimens (unless one is the collector or has permission) – even (and perhaps especially) if based on digitized specimen data already publicly available online.