The Event status serves two main purposes. It gives an indicator to members and guests of the status an event that is being scheduled and it controls what happens when changes are made as described below.
Draft
By default, all new bookings will start with Draft status. This is so that the owner and/or organizers can make changes to the booking before notifying other participants. Once you are ready for participants to be alerted to the event, modify its status to Scheduled and any subsequent changes to the event will notify all impacted users and groups.
You can make as many changes as you want to an event while it is in draft status. NOTE: you may also want to change a Scheduled event back to Draft status while you make several rounds of changes to it and then change it back to Scheduled once you are ready to notify attendees and organizers of the changes.
Draft events will appear lighter and more transparent than Scheduled events on the calendar and timeline.
Requested
The Requested status is very similar to Draft status. The primary difference is that it was likely created by a non-manager user or even a guest using the publicly available event request process. Often the Requested status is used to represent that the designated owner is an individual that doesn't have the authority to promote an event to Scheduled status or make other modifications. As with Draft events, participants and organizers will NOT receive notifications while modifications are being made to an event in the Requested status.
You are not required to "promote" an event from Requested to Draft before changing it to Scheduled, although you certainly can if that helps provide clarity in your organization.
Requested events will be even lighter and more transparent than Scheduled events when viewed on the calendar and timeline.
Scheduled
Once an event is confirmed and ready to be shared, you should change it to Scheduled status. Attendees and organizers of the event will receive a notification with details about the event. Subsequent change to the event will generate additional notifications to the users. You can "demote" an event to Requested or Draft status at anytime, just be aware that users will not be notified of any changes while in one of these statuses.
Canceled
At any time, you can mark an event as Canceled. This is not the same as deleting an event. Canceled events will still show on the calendar, but with a visual indication that they are canceled. You may want to do this so that attendees are not confused by something missing from the calendar altogether.
Canceled events will release any space and resource reservations that may have existed for them, so that others can book these spaces and resources.
If you want to remove a Canceled event from the calendar completely, you can simply delete the booking. WARNING: there is no way to restore a deleted booking, so you should use the Canceled status for any event you may want to restore for whatever reason.