In an earlier article talking about Payton deciding who to start, Payton says there is a different game plan for Taysom versus Winston versus Brees.
I'm not saying that NO will go to the read option. But they must've seen which throws each QB is better at and has had more success with, which plays they do a better job and finding the WR's and going through progressions, etc., which influence game planning and play calling.
If we're being honest, for example, Taysom probably throws it further than Brees. Winston does too. So knowing that's an option changes some of the game plan and play calling. Brees is more accurate - which maybe changes some of that too.
Again - I'm not saying they'll change the offense. I'm saying they'll change the game plan. (Heck - with Brees the game plan includes having Taysom come in for some snaps here and there to run/throw. That part of the game plan is out with Taysom starting - so do they replace it with something else? That's just one other example.)