I use both - Gaia and Google Maps on iOS and gazetteers and Benchmark paper maps. They both have their place, the paper map books are great for large scale planning, and the digital maps are much better for fine scale navigation - finding a specific trail head, or hiking.
The issue for me is that we often head out without a specific plan or the plan changes (this is Wander the West right?), so knowing which paper maps you will need before hand is challenging. We usually carry all the gazetteers for the general direction we are headed (say CO/UT/NM/AZ) but I don't want to load up all 50 or so Nat Geo Topos for those four states. For that Gaia Premium on both a tablet and an iPhone is perfect. We have all the Nat Geo Topos downloaded as well as Gaia Topo (~1:24000) for the entire Western US. If you were doing a really long trip (as they are in the vid) I can see that carrying paper maps beyond a world atlas would become impractical.
What I would really like is gazetteer sized tablet with gazetteer style maps - the best of both worlds.
I also agree that the inReach is a great tool. We carried a sat phone for a long time (I use them for work as well) but have since switched to an inReach with a powered Ram mount. Is is always on while in the Ram mount so we have a complete map of all our journeys on the Garmin website.