There should be public Nostr terminals like phone booths.
purplepag.es relay to look up an address like a phone book.
Sign the message with a signer device.
Discussion
Is there really a need for personal devices at all?
The family nostr terminal is a return to landline phones. Computers in the kitchen. Better times.
nostr:npub1mlcas7pe55hrnlaxd7trz0u3kzrnf49vekwwe3ca0r7za2n3jcaqhz8jpa