Well if they have a healer it isn't much of an issue as far as short rest. In my end fight for act 1, for example, it matters how fast they get to the end boss so if they take a short rest or even have to spend 2 minutes healing up after every fight it will make a difference.
Mostly short rest will change what time they get to a scene be it night or day.
Long rest will mostly happen in towns so not much of an issue. Long rest are how you regain source points and luck rolls. If out in the world and in need of a long rest they will have to camp overnight with the possibility of random encounters. If attacked at night all but the one on watch will have to take their armor off like in d&d