The built-in Jitsi integration lets you create a voice chat call via a single button click. You can also put those call links in a channel description if you like.
We do have plans to make the integration offer some additional ways to jump into a call, and have been talking about adding video chat. But our focus has been on building the best text chat possible, given there are multiple actively developed FOSS video call systems that we can integrate with.
Jitsi used to be so frictionless, but now that their public instances are a bit more locked-down (understandably...) I wonder if developing a deeper first-party integration would be sensible.
We do have plans to make the integration offer some additional ways to jump into a call, and have been talking about adding video chat. But our focus has been on building the best text chat possible, given there are multiple actively developed FOSS video call systems that we can integrate with.