The person entity is not yet integrated into the overall system, and several of the WTH comments are about how to couple the concept with other element e.g. login using Users, or with notifications.
A more thorough integration might be in order as this is really a core concept in an automation system - we communicate with someone, someone has access rights, someone has a specific token, many devices are associate with individuals.
Specifically:
A person should have a list of notification media associated - maybe with preference ordering
The person/user distinction should be collapsed
Trackers and other devices should be able to have person associations
Specific data should be able to be associated with persons e.g. if a passcode is given to a user then the passcode field might be added to all users so it can be matched to identify the user
Access rights should be associated with the person
Persons should be groupable e.g. children and parents, in a similar way to areas
This is obviously a big ask, and would have to be a feature close to the core, but seems like it would improve usability in lots of ways!
You can just edit the post for the request to link device_trackers with people. Just an FYI, device trackers are already associated with people, but not the other way around.