Neither, but my coworkers are apparently unable to carpool to a lunch spot 5 mins away that we visit every 2-3 weeks without setting nav first.

Many years ago now I picked up a colleague (the boss's son, actually) to drive down to London from Glasgow to collect some equipment.

First thing he did was slap a massive TomTom sat nav in the middle of the screen. He got pretty indignant when I told him to take it off, because it was blocking my view out the windscreen.

"But how will you know where to go?"

Dude, it's London. London is south. We go south. We go south for like eight hours.

We can use the sat nav for the last dozen or so of the 400-odd miles we'll be driving.

Maybe he didn’t know that you knew how to get onto the motorway, or that it’s straightforward to do so. Try driving I-80 in San Francisco during rush hour and make the 4th Street exit without getting forced onto the Bay Bridge, without either having done it before or without some sort of guidance- digital or otherwise. Getting on and off a freeway is not always simple.

Not to mention, even long road trips sometimes require a few highway transitions.

Once the city you live in gets large enough, memorizing the routes just becomes a non starter. I have my route to work almost memorized but due to construction or crashes it changes so often it is hard to cement it. (Seoul)

Because the traffic isn't known to you but it is to Google. I could take two routes, one is faster depending on circumstances, and Google knows those circumstances.

Is it really faster though?

All you have now is two routes with a roughly equal amount of traffic on.

One of those routes will be a massive detour.

How do you know those routes have a roughly equal amounts of traffic? Or that there’s only two routes? I usually see at least three possible routes with my commute (with some forking), and at least one shortcut. During heavy traffic one optimized route can at least save 10-15 minutes than the slower one(s).

It's really unlikely that you're saving any time at all.

This just isn't true. You're assuming the conclusion and saying the routes will have equal amounts of traffic and that one will be way longer and that it's unlikely you're saving time. Except people that have experience with Google Maps have watched it flag upcoming traffic congestion and explicitly reroute you and ask you to confirm and show the time difference. That's the real-time aspect, but it can also project forward in time and estimate what the traffic along routes will be at the time you want to travel, so it's also an important planning tool.

I have no idea why it's contentious that having nationwide surveillance of traffic patterns would result in better routing decisions.

And you know this how

Unfortunately, accidents are quasi commonplace among my commute.