In Outlook, it's possible to reply (not just RSVP, but sending an actual email) to a meeting via context menu of the calendar entry or via the ribbon buttons. (https://filestore.community.support.microsoft.com/api/images/a438f997-7a94-4be9-a79a-3b96507008d5?upload=true)

Being able to reply with an email to the invite directly from the calendar UI without looking for the specific invite is a great efficiency.