How would that look like in practice? I've just heard about the term and I like the description of it, especially the possibilities it gives

That's a great question; it's something I still need to explore, but it would involve some sort of distributed public key database and IP address directory, then a routing table on top of that as people add more resources to the mesh. Wireguard is particularly good at transparent roaming, so it's trivial to use on portable devices or if you need to migrate your server from one provider to another.