Anytime a team can set the market with a mediocre QB by giving him top 10 money, and then nearly immediately, but not in time to acquire quality ancillary pieces, restructuring the deal to free up cap space, you just have to do it. Jones' agent deserves a bonus.
That said, Jones is not as bad as he appeared for 3.5 of the past 4 games (69.7 rating, 37 QBR). He's also not as good as he appeared last year (92.5 rating, 62.9 QBR), particularly in participating in a road playoff win, that helped him secure that money.
That is absolutely possible. The two are not mutually exclusive. Jones is veteran enough and the money would indicate that he knows when his line is sub-optimal and needs to get rid of the ball quickly. OTOH, where is Mike Kafka in this criticism? He knows of the deficiencies on the line. Where were the short quick pass calls?
The Giants made a mediocre Seattle D resemble The Legion of Boom and instead of worrying about competing with Washington for the 3rd or 4th WC playoff spot, they are looking at a top 5 pick in the early going and a possible Jones replacement.