Webex Assistant for Meetings responds to everyone in the meeting whereas Webex Assistant for Rooms responds to people in the room only.
Webex Assistant in the meeting responds to voice commands such as taking meeting highlights, action items, and notes. For more information, see Use Cisco Webex Assistant Voice Commands in a Webex Meeting.
Webex Assistant on the room device responds to meeting control-focused voice commands such as "Join my Personal Room," "End the meeting," and "Turn up the volume." For more information, see Get Started with Webex Assistant for Devices.