When you want to Sync Multiple Google Calendars into One. Currently Google Calendar doesn't have this option and [IFTTT]/[Zapier] don't allow an easy way to do this.
This is useful for a collective Busy/Free Calendar or Google Home integration.
Are you one person with two (or more!) calendars that
- Get meeting invites
- Have separate audiences (most people can only see one calendar)
- Block your time (you can't be at two 1pm meetings)
Then you might like Sync Multiple Google Calendars Together! It creates time blocks on calendars to ensure everyone knows when you've already got events scheduled.