I am no expert, but having normal cell phone speeds available most of the time, then backing off to 'IP-over-SMS (IoTXT?)' speeds when off the cell phone networ

I am no expert, but having normal cell phone speeds available most of the time, then backing off to 'IP-over-SMS (IoTXT?)' speeds when off the cell phone network carries a lot of value for me, not just in search and rescue scenarios, but maritime use, use in the back 40, and so on. Sure, we won't be able to stream media, but having slow and steady wireless communications vs. no signal at all is like comparing a running, rusty 1985 Volvo station wagon to a 2021 Porche 911 GTS with no wheels: one will move you from place to place, albeit at a stately pace and in no style, the other is super cool, and at this exact second in time, is unfit for the purpose of transporting a body from place to place.