Of course the incidents where we get a GPS derived positions are much easier, but onshore at least, they are few and far between. We are usually relying on Joe Public's map reading abilities. The GPS/EPIRB combination is wonderful though not as widely used as it should. Many of our jobs are onshore or coastal. The GPS is great for getting us to the locale, but for situational awareness, planning the operation and setting up an approach to the casualty's location is best done using an OS map. The GPS will take you to the exact position, but it will not tell you what to look for or indeed if it is the right position. Nor will it tell you that you are about to hit something hard or stringy.
Of course for many PPLs the GPS is adequate, but you can navigate very well without one (in my opinion just as accurately). In some situations the GPS is preferable to map reading, in others, map reading is more suitable. Yes, map reading is a hard won skill, but it is wonderfully satisfying and adds a bit more interest and challenge to private flying.
To say one is better than another is like saying apples are better than oranges. To say that PPLs shouldn't bother learning about a valid nav technique is like not teaching an apprentice carpenter about the different types of saw.