When I was testing, the phone number was required but the Email Address was not. No value in sending a notification if they don’t enter their email address. Also, we NEED email address so that when the appointment is created in Google we can have them invited as a user. Since there is not a current flow that indicates how the appointment will be conducted, we need to make updates to add Google Meet or Zoom links to the appointment so we need to make sure the invitation is updated.
Happy to see you on our forum! Welcome, @Chris_Vaughan 
Your suggestion totally makes sense, thanks for sharing! We’ll try to consider this opportunity in the future and I’ll make sure to update you here in case of any news 