At least the thru-hikers of years ago could use maps and guidebooks. Explorers, settlers, and Native Americans who first traveled across these lands didn't always have those, yet somehow they managed to find their way.
When I first thought in the early 2000s I wanted to hike a long-distance trail, there was a lot of resistance within the hiking community against using electronics. Today, that sentiment is gone.
The fear then was hikers would become too reliant on technology, which was prone to failure. Batteries could die, devices could fail if they got wet or too cold. All of that is still true today, yet no one seems willing to give up their smartphones.
I know how to use a map and compass, but my smartphone is better. Apps allow me to instantly know where I am and how near I am to water sources, campsites, and roads. Comments in Guthook provide additional information, such as the reliability and quality of water sources and recommendations on the best place to stay in towns.
My phone allows me to focus more on the enjoyment of walking and less on the logistics of getting somewhere.