I'm not sure if it'll do much about aquaplaning - not that I'm saying it won't I just don't really know - but placing the aircraft firmly down in the TDZ will:
*minimise risk of a float and associated increase in landing distance
*correspondingly minimise the time taken to speedbrake deployment and ability to actuate reverse thrust
*by reducing time to full speedbrake deployment, maximise the weight on the wheels sooner and therefore increase braking effectiveness.
My two bob's worth.