Thanks for mentioning this drawback, which could be significant depending on which dishes are in the regular rotation. Most of the time veggies are what I roast in convection mode. Roast chicken or fish occasionally. A nice Sunday roast sort of thing – once in a blue moon. Even so, I do find that convection causes the oven (electric, convection) to get dirtier faster than the gas workhorse we had at our previous house.
I didn’t choose the oven here though I appreciate what it does well. Would I choose a convection oven if the choice had been mine? I am still not sure one way or the other. Could be all those years of cooking with the most basic of gas stoves. 
