When I edit the site, there is a settings section with a profile with things like email, street address and phone number.
However, none of this flows to the Contact page... so I re-entered the contact email, street address and phone number.
I'm just wondering where the data in the site profile is used, if it is use.
There are four possible layouts for the footer section. The phone number and address are displayed in some but not all of these layouts.
Welcome to the Community!
The answer provided by @reverselogic is correct. Some of the layouts will automatically enter this site profile data automatically. But all of the selection layouts will allow you to enter the information you want in that section - where ever you choose to add it. It just helps in choosing the general layout of the section to assist in the design.