Since XMPP is installed and enabled by default on YunoHost and there is an official xmpp:support@conference.yunohost.org MUC room there as well, it might be useful to have an XMPP chat built (e.g. ConverseJS) in the corner of the YunoHost WebAdmin.
That way admins could have access to the support chat without needing to install any additional software, and did not even need to search for the chat rooms.
I think the best option would be a link at the bottom of the page to a help section with enough information to contact the support.
(This link already exists, maybe the documentation pointed could be more complete, there is just a link to the forum in it)
I really think that a support tchat in the admin web interface is a really bad idea, especially because the time for an answer could be long, humans are responding, not bots.
Another problem is that admins could have disabled XMPP because they do not want it, or just did not opened the ports for XMPP.
(And I think I remember reading somewhere that having XMPP as default might be removed in the future)
So, I dislike the idea, but this is only my point of view and it is always pleasant to see people wants to improve YunoHost 
I see your point that I could cause annoyance on both the user/admin and support room crowd.
But I think both could be addressed by setting the expectations by writing something along the lines of it community support and asking for patience and perhaps needing at least another click to enable that chat, so it’s not 100% automatic.
Alternatively, how about just (optionally) including ConverseJS as part of “the small ‘YunoHost’ portal shortcut square on apps” (perhaps even for all users, so they know they can easily chat with eachother), without automatically joining the support chat. (that’s probably best for another thread)
some people don’t read the instructions at all and support benevolent are already struggling with them, so including a chatbox would make things worse for that 
Fair
Fair point.
Oh, well, it would have been cool.