Previously with Productivity Tools using the on-premise Outlook calendar, users could schedule meetings on any calendar they had access. This allows a user to schedule a meeting on another user's calendar and make the other user the host.
Webex Scheduler needs the ability to either choose the calendar and host for the meeting or be able to recognize the owner of the Outlook calendar where the meeting is being scheduled as the host instead of the user scheduling the Meeting.
This is already supported on Microsoft 365 cloud version of Outlook. For on-premises Exchange, this is not possible on an Outlook level until MSFT pushes the update to add delegate support to on-prem Exchange (support for this on the "current channel"or monthly release of on-prem Exchange is slated for late May)