Question

what is the usage of calendar sharing

Answer 1

You can share your calendar with your assistant or other co-workers so they could know where you are in the office, or to share some company events without sending an invitation to everyone. Or to your partner, so she or he could know when not to invite your friends for the dinner, or when to schedule a visit at the doctor’s for your children.

If you want to find the right time to meet with someone, I would rather suggest using some other tool that integrates with your calendar but don’t show any details despite the availability (eg. Appoint.ly)

Answer 2

By using calendar we can:
a) create appointment and events.
b) organize meetings
c) view group schedule
d) send calendars to anyone through e-mail.