It's a 2 hour battery with a dedicated cable and looks easily swappable in seconds.
Yes, even for that family of rich Apple executives, it will get tired by the third time.
For a 3500$ device? Fantastic!
The running time of the CD-ROM was designed to play Beethoven's 9th symphony in its entirety. You would have thought Apple would plan the battery life to allow you to watch all of Avengers: Endgame, or maybe Oppenheimer, without pausing to swap the battery.