This is the most basic use case for GUIDs relating to biological specimens or field observations.
Some example scenarios:
A taxonomist wishes to retrieve data relating to a specimen referenced in a monograph, including any available images, to determine whether to request a loan of the specimen.
A researcher has retrieved a sequence from GenBank identified as coming from a particular taxon, but the sequence is more than 1% different from all others for the same taxon. The researcher wishes to access the specimen to confirm the identification.