Things like Matrix use jitsi for video chatting. There is already existing end to end for messages, but the jitsi component wasn't end to end. Now Matrix can us

Things like Matrix use jitsi for video chatting. There is already existing end to end for messages, but the jitsi component wasn't end to end. Now Matrix can use its existing E2E messaging channels to distribute keys for an E2E jitsi session. In fact, group chat keys are distributed via two party E2E chats handled transparently by the clients, so it wouldn't even be a novel concept.