With any aircraft it would be better airmanship to stay with the manufacturer's recommended take off technique, rather than the instructors personal technique - in this case playing with lifting the nosewheel two inches clear of the runway during the takeoff run? Unless the takeoff surface is soft or rough why lift the nose-wheel early in the takeoff run when there is no operational need to do so?
I agree. That technique is most likely to be counter-productive except in the soft field case. Rolling resistance on a firm surface is small compared with aerodynamic drag at TO speed. Only when the ground is soft enough to push the rolling resistance up to some figure (ie about that of soft turf) does the extra aero drag penalty of significant back pressure become a worthwhile trade-off - purely from a performance perspective and notwithstanding other considerations such as eliminating shimmy or dealing with potholes of course. Stick with the manufacturers recommended technique.