“If you go that route, anyone can...use your device...”
If your phone is password protected can someone else use the telephone or text function without using the password? For instance, if you’re out and about and have a stroke or seizure or something, can the EMTs get a number from or call a relative with your password protected phone? Or do you get to die alone because they can’t get the information?
I have a smartphone, but don’t keep anything more sensitive on it than phone numbers and shopping lists.
There is an emergency section on the lock screen that permits you to place emergency info for that purpose if you choose. But if you don't enable it, no. But the EMTs can say "Hey, Siri, call home" and it will.