But there's also the point of view that battles that aren't a part of the story are pointless, and battles that are part of the story are always important even if there's no risk of death in them (death is not the only possible consequence after all). If the story you're telling is survival horror dungeon crawling then attrition is needed to keep the players in that mindset, but if the story you're telling is about an ongoing gang war between factions in a city for its control, and the battles take place over the course of a week rather than hour by hour, attrition is a lot less important.