The half-mile paper maps are the best maps out there in terms of zoom-level and accuracy. Get ’em, they’re free, though you do need to print them. Everybody will be referring to them (as in: there is water at mile 1539, the trail is closed due to fire between 1286 and 1341).
If you’re shipping resupply packages out to yourself, then you should add the relevant half-mile paper maps into each box, to avoid walking with the entire map, as it is heavy (200 pages).
Having a paper map and operating a compass somehow gets you closer to your surroundings as you need to orientate yourself, know the directions and relate to all the names of rivers, mountains and forests.
That said, the two relevant smartphone apps for the PCT (guthooks and halfmile) are a very nice tool. If you’re lost, it can quickly direct you back to trail. On the guthooks app, some water sources are mentioned and even updated whether they are running or not, by other hikers through the app. You will never be asking yourself “is this really the trail or did I, accidentally, loose it?”.
New tech or not? I stand neutral in that discussion. The comfort of a papermap is invaluable, sitting there around the fire in the evening, looking at the contours and names of mountains. It doesn’t run out of battery and there is something lovely “oldschool” by navigating with a map and compass.
But don’t be fooled. The apps and the gps-enabled smartphone is an extremely straightforward tool to quickly assess your distance to the next creek and get your exact position. If you’re trapped in a white-out, it could save your life as a map-and-compass is next-to-useless when you can’t see the topographical features around you. A gps signal can.
So, learn how to use the map and compass for safety, for the experience and since you’re likely carrying it anyway. Conserve battery and keep your smartphone charged, also for safety and comfort and since your likely carrying it anyways. If you know how to operate both, then two navigation technologies are better than one. And neither a compass nor a smartphone is rocket-science to operate.