What are you talking about exploitable? The stamina mechanic is redundant when there is already an energy system in place. Your double waiting for no reason other than to drag the event out an making it a full time job for people without very end game rosters.
The original point though was also to be able to use it as sort of a sandbox mode too, to test different team comps in different situations.
Nobody said anything about the rewards, most people can get red crate but the time involved in doing so is double inflated for no reason.