Not something I would admit to in most transport category aircraft
If the configuration is declared in the AFM then it is available for use in appropriate circumstances. There is absolutely nothing untoward in using a certification configuration for takeoff. There may, of course, be maintenance consequences in the medium term eg increased wear patterns but that is a quite different commercial consideration.
Often the only way to get max weight is to go minimum flap (which may, or may not, be nil flap) .. for most aircraft with which I have had any experience, the maximum certification weight can only be achieved with minimum AFM flap takeoffs as the WAT limits cut in for larger flap settings. In general it is a case that you choose larger flap settings for short runways with benign obstacles, mid range flap for medium runways and/or modest obstacles, and minimum flap for longer runway with significant obstacles. All a case of horses for courses .. so long as all the various limitations are satisfied for any given takeoff with a particular configuration.