I think a lot of this ends up behind how you learn navigation. I love GPS as a way to build up heuristics of how to get places in a new city/from a new location. I find I mostly learn routes by visual memory and not by street names/distances/number of blocks. I know to turn at a specific building/business, and not because it's 5th street or a specific train station.
If you're someone who learns your routes in terms of facts/numbers, then I can see GPS hurting your memory, but in my case, the GPS won't tell me to turn at the Walmart, or get off at the train station with the green tile. So after a few GPS trips, I've learned the route in the way my brain will remember. This especially helps when I don't know the traffic patterns or alternate routes that a navigation app does.
These days, for routes I don't know really well, or have high traffic variance, I'll check GPS to verify a route, and then use the route without using the app directly.
If you're someone who learns your routes in terms of facts/numbers, then I can see GPS hurting your memory, but in my case, the GPS won't tell me to turn at the Walmart, or get off at the train station with the green tile. So after a few GPS trips, I've learned the route in the way my brain will remember. This especially helps when I don't know the traffic patterns or alternate routes that a navigation app does.
These days, for routes I don't know really well, or have high traffic variance, I'll check GPS to verify a route, and then use the route without using the app directly.