In 5 decades, I've never had to dial 911 ONE time. This is the most common pushback I get about my choice of how to use Apple tech, and I would bet that MOST people with iPhone have never needed 911 service.
That said though, I have set it up to give me a speed dial to local services, so I hit
ONE button instead of three if I ever need Police, Fire, Ambulance. At home, I have one-push buttons for the same on the alarm system and the home phones (which share the same VOIP line) have speed dial for such services too.
So my real risk along those lines is being AWAY from home, potentially being in some kind of situation where I need those kinds of services and needing to do a quick search to identify the nearest ones. That would take a bit more time than clicking 3 buttons... but, how many truly solo emergencies are there in the world? If others are involved, they will be dialing 911 too.
Besides, we all have Siri... and we know a Siri request will connect us as fast as possible.
My car also has emergency services, so if the event involves the car. I can push one button there.
My choice is not for everyone. As in all things, there are certain tradeoffs. For example, Watch and CarPlay are designed to just about HAVE to be married to iPhone. So if one values either of those, my way is probably not going to work for them. In my case, I wear a traditional watch and can do all my watch-app like things on the bigger Mini screen that is with me anyway. And my car's stock system covers the core CarPlay things I would want to use: map directions over speakers, music playlists, calling with the car's buttons, etc.
I could easily rationalize having a phone (too) but I just don't think I need one. VOIP app makes iPad Mini a great phone (with buds) and I otherwise have a bigger screen running the same apps on the same A15 for much less cost (service and (less regular) upgrades). Some tradeoffs are tangible, but I choose to make them for the benefits I get.