I dont see where it would hurt, but i am by no means a professional engine tuner. I have thought about it too and the only thing i can come up with is the con rod big end could possibly wear faster. It has to work harder to push the piston up because of the extra fuel in the combustion chamber. But there is also more lubrication reaching the con rod from rich settings. Heat is the #1 cause of death in all types of engines, so the cooler you can keep it while still making the power you need the better off you are IMO.