With the amount of storage you need to use the maps offline for large areas, it would make sense to be able to use it on a MacBook. We're heading out Monday for 17 days across Vancouver Island and Western BC and the size of the map we'd need are just to big. We also will not have the option to find free WiFi regularly to update our maps. My MacBook already has a built in GPS plus I can tether it with an external unit if necessary. I can use cards and create maps that are saved to each card. With an iPad we don't that ability as far as I've been able to find. My MacBook also serves multiple other purposes that an iPad doesn't which is why we bring it when we travel and not our iPad.There is a cloud version for planning purposes but not for vehicle use. Technically possible? Maybe, you would have to pair a GPS to your mac and see if it would work. I think you would be much better off buying a iPad mini or Android tablet.
May I also recommend the ability to free hand draw the area of the map that you want to use offline. It will save some people significant storage.
So far from the little I've been able to use the app, it's really nice. Kudos to all that have put the work in.