Cousins would be great for the 49ers, I would take him.
On the flip side, if Darnold or some other QB, has the making of another great QB then the appeal of taking them and their cheap contract is too much to pass up.
It looks like the 49ers are building a roster up in preparation for a QB to come and be ready to go. That would be the benefit of having Cousins next year. If they are another year out then drafting a QB would be a smart move too.