The point with moving pitch to full fine on approach is to be prepared for a go-around or the need for full power, me thinks. Most engines will probably handle a light overboost (ie MP higher than RPM) but the old radials weren't that forgiving, I think the idea has remained from that era. So long as you don't forget to shove the prop forward with the throttle it shouldn't be a problem. But, how many don't forget?