This doesn’t make sense… how are they running power to the door lock? I would have guessed that these devices always run on battery don’t they?

For buildings with 'heavy duty' entry systems, power to a powered lock can be hooked up through a 'door loop' [1] on the secure side of the door.

Or you can put the electronic lock in the frame of the door, as an electromagnet or an electronic strike [2].

The door to a residence, personal office or hotel room might only need to open 10x per day and so can be battery powered - but the main entrance to an office building might open 1000x per day, so wired power is the right choice there.

[1] https://doorentrydirect.com/srs-460mm-door-loop-with-cable-p... [2] https://doorentrydirect.com/alpro-al151-inwardly-opening-ele...

If it’s a commercial building it’s easy enough to run power through a special hinge.