It's currently optional to connect your calendar and add your phone number to your account. However, if you don't connect these things, Notiv won't automatically join your meetings.
How to Connect your Calendar
If you don't add a phone number to your account, you won't be able to make telephone calls through Notiv!
So, it's totally up to you what you want to add to your account, but it does affect the ease of using Notiv!