Editing vocab inconsistently requires content type(s) to be selected

If one wants to change the title of a vocabulary, they must check at least one content type before the form can be saved. However, one can come back after saving the title change, uncheck all content types, and re-save the vocabulary successfully. Since in the case of the glossary module, the glossary vocabulary has no associated content types, this latter behavior is actually desirable. There might be other modules which use taxonomies but without their terms ever being assigned to content nodes.

So to be consistent, and to allow contrib modules to work in a sane fashion, why not remove any requirement that one or more content types must be selected to save a vocab? There should be no harm in doing so. At worst, there will be vocabs and terms stored which will never be applied to content.

This might even be considered a benefit: site admins can create proposed new vocabs for review before actually applying them to content.