Is it possible to use such configuration? Or there are no advatages between ssh:// and git://?
Yes, it does. However, the URL bar in github web page no loner have git protocol for copying the URL to clipboard. You have to replace https:// with git:// by yourself.
Also, git protocol use port 9418. Make sure you can use this port.
git protocol is not encrypted, but it is faster than https.
git protocol is read-only in github. You cannot push to it via git protocol.