I make a point not to rely too heavily on GPS.
I’ll use it going to a new address. But, I’m paying attention to the route and relating it to other locations I already know.
I try to learn new areas quickly so I can drive without the GPS.
I’ve driven most of my life by memory and without maps or GPS.
It is very nice having GPS as a backup if I do get lost. I can always get home. 
Exactly… regular old single-frequency GPS is only accurate to about 4 meters or so. A lot of the time that’s augmented with cell phone tower and wi-fi information (the Android “High Accuracy” mode) that gets you in closer than that, but still not that close.
Dual Frequency GPS gets you within something like a foot or two, but it’s not yet common for most everyday civilian applications like smartphones, although it’s common in military applications. From what I’ve read, the EU’s Galileo system is a fair bit more accurate than GPS, being some 30 years newer, and is easily receivable by the last few generations of smartphones, EXCEPT that the US FCC was prohibiting US phones from receiving the signals until some kind of decision in Nov. 2018. Now all we have to do is wait for a software update to allow US smartphones to actually use those signals…
GPS augmented with some sort of land-based system (WAAS, differential GPS, etc…) can get very accurate, but again, they’re not too common outside of certain specific applications like surveying, etc…
As for the utility of GPS, one consideration is that even if you’re well aware of where your start and end points are, and multiple ways to get there, most modern navigation apps like Google Maps or Waze will take traffic into consideration and route you along the fastest route. That’s the real utility for me; it’s pretty easy to use a map, or even Google Maps to find your location and figure out how to get there, but I don’t have that extra information to tell me that there’s a wreck on route A, so I should take route B instead without using the smartphone navigation app.