I asked the Boeing 737 Chief Tech Pilot this question today. He said he is asked this a lot.
The Boeing recomendation is to have the A/T switched off (don't leave armed) for the reason that it may under certain conditions (flaring too high, float or gust of tailwind) command an increase in thrust during the flare as a reaction to the loss of speed, which will destabilise the landing. This has lead to tailstrikes and could lead to an overrun.
Ignore this advice at your peril. If you have an accident due to this config, you will be asked why.
Surely now, debate over.