Andy Dalton is PFF’s 2nd highest graded passer this season

At this point in the season, not playing Winston if he is healthy, so you can evaluate him for next season, is completely ridiculous.
Allen has already made a decision on Jameis and Taysom at this point, that's quite clear.
Trying to highlight what's "not bad about a player is not a positive attribute. At his prime Dalton was a solid, not special QB. He's in his mid-30s as a QB, who is below average in all the key metrics like wins, red zone, etc. Allen is so bad as a coach that he's not even to swim, he's just trying to stay afloat. That's why Dalton is perfect for him.