Except they guaranteed Cousins $100 million so they will not be able to take advantage of the salary cap benefit of a young QB or use that money to help build the team around Penix.
The Cousins' contract makes sense for them if they don't then use a bunch of picks to take Penix at #9.
And, if you think Penix is going to be a great QB, trading up to take him at #9 makes sense if you didn't just give a $100 million in guaranteed money to 35 (36?) year-old QB.
Each deal makes some sense separately, but they don't make sense together unless they found out that Cousins was not going to recover only after they signed him to the contract.
And frankly, #9 was way too high to take Penix. I honestly think his ceiling is Derek Carr before this year, and he may never even be that.