It's a circle jerk. You can send a bolt12 address and receive sats to your node. But no, fuck that. Let's have the sender first open a channel, send sats to a mint, have that mint issue a token, send that token to someone through signal, and then have the recipient redeem it. Why? Just because the bastard receiving the sats doesn't have inbound liquidity and has zero interest in owning a channel. Why the fuck would I be sending such blokes sats in the first place?

Because most people don't have any wallet. The idea is to give a wallet to every Signal user, to help (force?) adoption.

It looks like shit. Terrible UI that normies will never ever use.