I personally wouldn't rely on my phone/watch if I'm headed anywhere remote without cell service & electricity. With Garmin inReach you don't just get better battery life - you also get the Iridium satellite network and a team that's more experienced at search and rescue.

That being said, I do think that these new emergency SOS features will come in handy for people who don't know what they're getting themselves into, or who just run into unexpected bad luck on what was supposed to be a quick day trip.