Accessing a “home computer” behind a NAT you don’t control or has a dynamic IP, eg. computers/devices that only have mobile connection and many (most?) broadband home connections.
I sometimes need to connect to a CI runner to debug some CI build script. I made a (quick hack of a) tool [0] for doing that by creating an Onion service on the runner listening to SSHD, and printing a one-liner I can paste on my dev machine to connect to it via Tor. This sounds like basically the same idea, but using a DHT and hole punching instead of onion routing.
[0] https://github.com/milesrichardson/shonion