OK
Use Case #1 - existing users
Being able to jump straight into chat would be very useful for those who are logged into the main site but who only visit the forum infrequently.
This means that it is able to function as chat for the entire digital estate of that entity, rather than just for the forum bit. This would increase the accessibility of the forum as a useful side-effect.
I can see this being super helpful for a couple of NGO / charities that I’m involved with. And I naively suspect that it wouldn’t be too awful to develop.
Use Case #2 - anons
Having a chat interface for anon visitors to a site is a common way of drawing people in to conversation in real time without them having to log in or join. Here is an example 3rd party offering:
It is quite common to ask for an email address to initiate it (most folk seem happy with this). This is an opportunity to create a staged user.
It would also be a great target for some automated / bot discussion.
Now, this would likely need to be a complex plugin!!