I don't get it; the computers are flying the airplane (FBW) so what difference does it make? From what I have been told you simply set the profile and the computer maintains it, no need to make any corrections due to flap setting, gusts etc. Trying to compensate causes over -control? I am not knocking Airbus, just a little confused.
Also, a difference in approach speed of 5 knots is not significant unless the runway was less than 1600 metres, surely? For the vast majority of approaches either flap could be used, or else you would not be able to land there with an engine out.