IIRC one of the advantages of the 25mm weapon (Apart from longer range and more flatter trajectory due to higher velocity than 40mm) is that collateral damage can be less as well (which might be desirable under certain ROE.. alot of time and effort is devised into making weapons that limit collateral damage without sacrificing lethality. Whether its
tungsten micro shrapnel warheads or
kinetic ginsu hellfire missiles. Alot of the weapon's utility (IRL at least) is determined by role/purpose and politics.