Hours and minutes are a unit of time but I regularly hear people talk about such and such a place being X hours or Y minutes away. The need to go on to then tell the listener that the speaker assumes the distance will be travelled in a vehicle being driven safely and in accordance with the roads' speed limits isn't needed in most conversation. It is assumed from context. We all speak in a vernacular and idiomatically. We're not walking text books written by grammarians.
It's not too difficult to assume that people in SF don't spend time burdening each other with pettifogging details that would be, in context, bloody obvious to each other. (Well they do, often, but it really stands out when characters infodump at each other.)
In everyday life I wouldn't say to someone on foot asking me how far it is to the nearest post office - "It is 1.25 Km in a north easterly direction and, assuming you are travelling by foot, are reasonably fit, and don't suffer from any kind of mobility impairment not obvious to the naked eye, it should take you (at an average walking speed of 5 Km P H) a quarter of an hour to reach it if you don't stop to talk to anyone on the way."
No. I just say, "It's about 15 minutes down the road. Opposite the pub."
Similarly if they were in a car I would say ""It's a couple of minutes that way. Opposite the pub."
I wouldn't go on to give the driver detailed instructions about which side of the road to drive on and how to negotiate the pedestrian crossing he will encounter on the way.
Maybe, given the hand waviness of so much of the science in Star Wars (the variable speed of light in The Farce Awakens being one such example), ships have to get to light speed before they can enter hyperspace and, while in hyperspace, the measurement of time is best expressed in units of distance. Luke and Obi Wan would have known this without having it explained to them.
