I don't buy that one. Yes, a modern tablet is very convenient in cockpit, for planning and I do love it for situational awareness, BUT, I would never hang my life during flight on such a device.
I don't think anyone does. I have three GPS solutions if I wanted to switch them all on, one stand alone, one tablet and one phone app. Unless I'm going somewhere new with shedloads of airspace to dodge around I don't bother with any of them. Not that I'm a Luddite or anti GPS, far from it, I'm just too lazy to faff around with them. I've seen blokes get them out and spend an age messing around just to go an hour up the road to somewhere they've probably been a dozen times. VFR navigation ain't that difficult you know...
Edit: But just to prove I'm not a purist, I always do a plog using Skydemon. Well, nearly always. I think I shelved the whizz wheel the day I passed my skills test.