I assumed it’s intentional. It seems to me that when originally written, it was supposed to be a binary method for changing an incorrect (e.g. misspelled) name, not a quick way to get started on any draft taxon change related to this taxon. So if you created the taxon, you can change the name by just typing in the box and saving, but if you didn’t create the taxon, the link to a taxon swap is a convenience to allow you to correct the name more easily.
Related request here (which, based on the “preferred option” screenshot, seems to possibly be suggesting getting rid of the taxon swap button whenever you have permission to edit the name directly?)