I believe that the config 3 technique in gusty winds is recommended because the approach speeds are higher and there is less drag. I've not used it unless there was a good chance of windshear (summer monsoon season in the desert here). I just finished a two day trip with strong gusty crosswinds on my legs. I used flaps full because I like having the extra drag and having the engines spooled up.
One thing the airbus does is the auto thrust system is very sensitive to side stick movement, especially in the flare. If you pitch up to arrest your rate of descent before you pull the TLs to idle you will get a spool up of the engines. So when you preflare, any back stick movement will result in an increase of thrust, giving you more energy at a time when you are supposed to be dissipating energy. Since the thrust levers don't move on the bus this spool can go unnoticed by a new or lazy pilot who isn't paying attention.