What does linking paid sessions to a calendar event do?

When creating an event on the calendar, you are given the option to associate the event with a specific paid session.

Linking the session is completely optional. If you do end up linking a session, when parents view the event they will be presented with an easy to use registration button.

If you are using your team's public calendar (url available under Settings -> Team) the public calendar will also show a link for people to easily register for the session associated with the event.