It's like "onion URLs" without the rest of Tor. Or like b32.i2p domains without the rest of I2P.
I hope to god this catches on. At this rate it won't, because a FAANG company isn't supporting it. But I still hope somehow it will catch on. DJB's work is fantastic and this is no exception.
I don't believe it will catch on. Consumers don't care about security. Engineers do, but not at expense of usability.
It's very simple. Allow not using encryption. Plain text + encrypted make a great team. Either by themselves is not great.