missed that in the title. Never played H2H so I'm not familiar with it's special benefits over the DA. What would they be?
Custom maps.
Custom arena settings including - sky color, time of day allowed (i.e. nighttime? dusk?), tweaking lighting, fuel burn, ack lethality, gun lethality, ammo load, etc, etc
Ability to kick players causing a problem
Ability to reset maps / settings on a whim or when requested by players in game
Ability to set different allowed aircraft
Just the ones I remember.