Citation of individual specimens, where this can be done (e.g. taxonomic treatments) is certainly important. Other use cases in this area include citation of the individual specimen from which tissue has been extracted and genetic sequencing work has been performed. In this case the issue is convincing other researchers to include a pointer back to the original specimen (as is often required as a condition of obtaining the tissue) in the repository for the results (e.g. GenBank).
More complex is the issue of citing specimens when they’ve been downloaded from an aggregator (such as ALA or GBIF) and used in an analysis in aggregate. ALA and GBIF already mint DOIs to identify the download, and institutions can work back from there to the specimens. In this case, the challenge is to encourage researchers to cite these DOIs in their papers (rather than individual specimen identifiers / registration or accession numbers).
Ultimately, there are many benefits but it comes down to users of collections doing the right thing.
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