I like the idea and here are my reasons:
1. His best offense is the same offense the Bills run with Tyrod.
2. Like Tyrod, he throws a nice deep ball - his short & intermediate passing needs some work.
3. RG III was a back-up and only active for 1 game this year (no snaps). If he was going to cause a problem as a back-up, he would have this year. Sure, RG III would like to start (I don't want a QB on the roster would doesn't want to), but I believe he will accept a back-up.
4. RG III has made good money in the league so far which makes me believe he is not looking for a big payday right now.
Just my opinion.
That was true in years past with RG III -- There was none of that in Washington this year.