So, lets say that we are flying under a calm place, you are looking for lets say maybe minerals or just waiting as your crew refine some materials, but you notice that you are lacking manpower as some of the crew are still sitting on the weapons or shield.
Or the oposite, you are willing to start to engage in combat but your crew are still running from refining and because of it it takes some time for them to properly get to their combat stations, and even so there is a chance of them to in mid combat to do something else.
because of it you tend to either spec your crew for combat or for doing other shores, but with this idea those could be things from the past!
Each crew would have two sets of OPTIONAL priorities, if you activate it your crew would have an option to have an "Battle stations!" set of priorities, who basically means that once you engage combat or press the "Battle stations!" button, your crew will change their priorities to the ones on the "Battle Stations!" priorities list, making so that you can let your crew to fully take care of the refining of the materials and recharging batteries while it is all calm and once this option is activated they all start to run towards their Battle stations!
TL;DR: make so that each crew can have two sets of job priorities, one as the default and the other for when you activate it or when the ship engage in combat.