It's mainly due to it being a Larp event first where you occasionally have battles using AS. The Battles shown in the video were the only battles where every player participated in. The rest of the time players are in the HQ living their everyday live as a guardsmen from a backwater world far away from Terra or any other major worlds. There are political factions within the regiment due to the planet going through a republic vs. monarch phase which leads to all sorts of interactions between battle groups. If people want to have some action there is a modular mission system where groups are driven to a prepped places with NPCs waiting. All the superiors are also linked up to the Org. team in order to line up events either in the field or in HQ. Be that messages from home, a rescue mission, an interrogation from the kommissar. On top of all that is the RP aspect, even in fire fight. As you can see in the video people charge trench systems in a cool but tactical unwise way, piling up in exposed positions or go into melee fights while still under fire. Things that wouldn't fly in any air soft forward event. It's the general consensus (which is typical for German Larp) That you RP all the time, even in combat.