Almost calendar apps on the market are for businessmen and public events. This one is for you and your friends and family.
I think is an alternative solution for group sharing, which focuses on offline events and small parties.
Been having such idea but not capable to implement yet. Trying out to see if it is exactly what I want.
UPDATE:
The sharing is limited to one group one calendar. If I want to share my course calendar with both my classmates and my family, I can only manually create it twice.