It's an alternative in extreme situations, but I wonder what if somehow the signal gets intercepted and the data within it gets altered?
The whole point of GoTenna is that it works without internet, but in the end you still need it, which is somewhat contradicting, and when you are out of range, or all devices aren't online, then there is no such a thing as using Bitcoin 'without' internet at all. It's not that they offer anything ground breaking, but just smartly make use of available technologies.
In order to actually transact offline, you will have to exchange private keys, but that's all based on trust. There are however various alternatives in physical form functioning as 'temper proof' offline means of exchange. I would rather use that in extreme situations.
I am not sure how good is security of their devices but based on what they say in their FAQ it should be very good :
Private 1-to-1 and group messages sent over goTenna Mesh are end-to-end encrypted with 384-bit elliptic curve public-private key ciphering. The only exceptions are messages sent using the “shout” and “emergency” features which are by definition public conversations with others within range of you.
I just check their site and see they have few products to offer, and also by the map of devices around the world this products are very popular in North America, but also in Europe. I agree that this can only work if there is users who use such devices, but I have some feeling that this could become very popular in future.
https://gotenna.com/
