I just noticed that we have a tag viewpoint, currently on 104 questions, with a tag wiki reading:
Questions about grammatical persons (first person, third person, etc.) and how to use them.
and the tag grammatical-person, currently on 76 questions, with a tag wiki:
Questions about the point of view of the narrator of a work.
From the tag wiki, each of them seems to describe exactly what the other's name says.
This could be a sign that they really should be synonyms. Or they are actually intended to be different, but either the tag name or the tag wiki doesn't state the intent correctly.
As additional fact to consider, the tag wiki of pov says:
Use the 'viewpoint' tag if your question is about the grammatical viewpoints (first, third, etc.), which to use, or how to use them.
In any case I think something should be done about it, though I don't know what.