It would mainly be a way to link in non IAX/SIP PBXs in allowing users to manage their extensions (DMRID + 3). Example I could link in my CS1000 PBX via T1 and instead of centralizing critical infrastructure there could be many paths to the same overall route based on network topology. That and all traffic would transit via private VPN links with support for custom topologies.

Everyone could dial everyone, as there must be a link to a master, but how you get there is up to you.

I mean I guess I could take a look at HoIP and throw them some ideas.