>Likely your Apple Watch won't be able to call for help if you're injured trekking or climbing, unless there's a cell tower on the mountain.
Don't know about the US, but in several mountains I've been on around the world (not in developing countries though), signal was just fine. It might not work for Everest, or the remotest part of the Rockies, but most hikings/treks are not in such places...
This is true. I am going trekking in a remote area and bought a Garmin InReach Mini. I know it pairs with my phone so it would be cool if there was some Apple Watch Siri shortcut that could make a satellite SOS message via the Garmin when a fall is detected.
Yup, for us hikers it would need to be able to use satellite communications to be of much value. Something of that nature would seriously tempt me to upgrade from PLB to inReach.
Having personally been run over cycling, multiple passersby called 911 for me immediately, and I was in a ambulance in less than 10min.