I'm not sure why anyone would use just Track Me. I just added Map as a data field to my Run, Walk and other activities. Seems to me it would be a default data field but it's easy to add.
I used it today for a motorcycle ride. I assume it is for when you want to be tracked but don’t want to get false credit for exercise activity when you are just riding a ferry or something.
Yes it's a bit confusing but as far as I can tell it's unrelated to live tracking. It's just another "app" with some preset screens including a map.
It’s basically just a simple sport mode that includes the ‘map’ view (so breadcrumb on non-5X units, or with maps on 5X units).
I suspect Garmin made it to simply keep things simple to explain to someone in a support/store/etc scenario as to what mode to use to get a map while doing an activity.