Make your calendar discoverable and proving the ownership
Once you have a public calendar, and you want everyone to know about it, you can also make it discoverable. You do that by creating a link from your website to your calendar according to a proposed standard.
It means that your public calendar can be easily found by a computer. Then, for example, someone could add your calendar by only knowing your website (domain name).
By linking from your website to your calendar you also prove the ownership of you calendar. Your audience trust your website, to a certain extent, this way they can be sure that whoever controls your website also controls your public calendar.