That is true, but there is a good reason. For example, you may call 911 in North America without any cell plan, or without a SIM. As you long as you are within physical range of any cell tower (whether your phone shows bars or not) the 911 call will go through. This is required by law. So, like your quoted text indicates, 911 calls would just need to be routed through your phone’s native dialer instead of, let’s say, Cheogram’s dialer (jmp.chat’s phone/message app).