A lot more difficult! But I think I recall SMS was used to send payments in Africa. But if we assume they’re both connected that makes it easier if that is indeed the case.
Discussion
Yes, offline, http://8333.mobi/ via feature phones and sms functionality. Here #[8] explains https://youtu.be/yknBN08hWOY
Speaking of Machankura: what if a nostr client low data / offline mode has send sms to nostr note + publish service & functionality