From what I see of the definitions pointed to here, I would propose to turn the synonyms around.
@Vitaly Mijiritsky commented that the classical definition of "copywriting" is mainly off-topic here.
@Patrick McElhaney said in his answerhis answer:
.. it seems all of our copywriting questions are about microcopy.
So maybe it should be that copywriting should be re-tagged to microcopy, and not the other way around?
So if it is actually "copywriting" the question is about, it should
not be tagged copywriting, but closed as off topic...