The access you give x.ai means that Amy and Andrew have visibility into your calendar and the details of your events. In practice for scheduling your meetings they predominantly use only the Free/Busy information. Currently, they only use the title information to let you know about conflicts (e.g. "Just wanted to let you know the time you suggested conflicts with your 'Daily Stand up Event'").
In the future, Amy and Andrew will ideally use information like the event's location to calculate travel time as well. In all instances, we are only using the calendar information to help schedule your meetings. x.ai does not own your data, and there is no business model outside of optimizing Amy and Andrew's ability to schedule for you.
You can revoke our access to your calendar at any time. If you revoke access, we retain no information about your calendar in our system. However, Amy and Andrew won't be able to schedule your meetings without access.