It's completely useless and has a tendency to FLOOD ALL OVER THE CHANNEL.
The only times I've found it useful is when I was live reviewing and wanted to point someone to a change/comment I made. Copypasting the links in such cases is all right as well.
Version: unspecified
Severity: enhancement
URL: https://www.mediawiki.org/wiki/Git/IRC
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=46450