Anyone with a basic understanding of the postal system will get it.
As long as the wallet has an ecash sats balance, stamping messages is completely automatic.
Discussion
That's exactly my point. They will need to understand "sats" and then they will need to understand "ecash". Both may happen, but it will take a long time. Most people still don't know that there is something like a fraction of a bitcoin.
That’s true. Right now, Keychat’s user is mainly Bitcoiners.