He will actually do his homework on the teams. He will be able to translate what he knows to the moment, as that is an enormous strength of his. And he will be able to speak to some of the how's and why's teams do what they do as he is among the best coaches in the game tactically.
Networks don't care who they have signed prior. They have already estimated his value, they know what he's going to be worth in the booth so they will still be hot after him the moment the season comes to a close.
That said I think Peter has it right. I wasn't feeling like this a month ago but after they picked up Mayfield it feels like he's been re-energized a bit. Still think the networks will pitch hard and McVay is going to be considering them. But he still seems to have that drive to win so I am hopeful he sticks around. Very worried about it, granted, but hopeful.