From @WUlate in this Spanish thread
An estimation of the number of specimens by taxonomic group, Class, Order, subtribe, any kind of classification, is usually not useful for the experts (and can even be seen as a work, unpaid for burden, therefore incentives are key) but could prove extremely valuable for the collections management in different ways: space management, planning, staff hiring, aside from the abovementioned search for experts and potential partners and donors.
Also From @WUlate in this Spanish thread, probably related to:
Only when the benefits of the Catalogue have been internalized will it be kept up to date… in the meantime, we will depend on a combination of advantages for those that get on board first (carrot for early adopters) and that the managers and donors enforce directives (sticks for non-compliants).