AFAIK there aren't that many robust approaches for reverse proxying web sockets. Apache mod_proxy doesn't work with web sockets, nginx (until now) only worked with websockets if you compiled and patched an unstable dev branch yourself, and not everyone was happy to get their hands dirty with HAProxy. An alternative was to build your own reverse proxy in Node.JS using node-http-proxy, but again, not everyone's cup of tea.
Use cases of websockets enabled reverse proxies are for when you have a number of websockets based apps all sitting on the same box or in the same private local network and you need a way to route incoming traffic to them based on the hostname or path or whatever.
Use cases of websockets enabled reverse proxies are for when you have a number of websockets based apps all sitting on the same box or in the same private local network and you need a way to route incoming traffic to them based on the hostname or path or whatever.