He wasn't interested in signing with a bad team
And signing to the Practice Squad gives him flexibility if he changes his mind.
This make sense for all involved. He gets to go to a good organization, with a coach who does good work with QBs, while still giving himself options in the short and long term. See what's out though in March or if he likes it there, he can stick around and be the JJ McCarthy insurance policy.
Also no pressure. If he goes to say, the Raiders, he'll probably play right away, but it's just New York all over again, and more opportunities for bad tape.
For as bad as he been and the memes, he's still probably a top back up. Would you rather have him than Mullens or Rypien? Or based on some of the other teams interested, 36 year old Josh Johnson, Brandon Allen or Josh Dobbs?