Not long ago I drove a long distance along plain old US interstates. With about 400 miles in between two major cities there were a few stretches of 5-10 miles where I didn’t have cell service, sometimes 25-40 miles in between local town exits or gas stations. Had I not scouted the routes ahead of time, I would have had no idea where to go or which direction to walk if there was a problem, much less an emergency like crashing where I couldn’t walk.
There are still large gaps in coverage as large as not-walkable-in-a-day in what you’d think are at least minimally developed areas. And they are minimally developed, but you’ll have no idea of what direction that developed portion is if you’re stuck without cell service or an actual physical map.
No one should go on any long car trip letting GPS guide the way without scouting the route a bit ahead of time to know what’s nearby in sparse areas. Apple is filling that “oh f$ck” gap a bit. Nice feature.