The current description of the snap at https://snapcraft.io/element-desktop only mentions chat, not audio/video capabilities:
All-in-one secure chat app for teams, friends and organisations. Keeps conversations in your control, safe from data-mining and ads. Talk to everyone through the open global Matrix network, protected by proper end-to-end encryption.
As such I expect users may be surprised to find that it has access to their camera and microphones by default - so either this description at least needs to be updated or when the user goes to make a video/audio call, the snap should try and detect if these plugs are connected at runtime and if not, prompt the user to manually connect them.