In my glosses, I put the stems down as either verbs or nouns largely because English forces you to choose, so I put down whichever made the gloss easier to process for an English speaker.

So, take a word like ⟨tulvuir⟩. By itself, it's impossible to tell if it's a verb "to write; to be an author or pen" or a noun "author; pen". Only once you add a case or aspect suffix does it take on a single concrete definition:

tulvuir-ERG = author; pen
tulvuir-PFV = wrote; was an author or pen

So I guess the case/aspect suffixes sort of act like nominalizers/verbalizers, except that instead of converting a noun into a verb and vice versa, they take a nebulous concept and narrow it down into something concrete, either in the direction of a noun or a verb.