Possibly, because running an extension cable from a passenger seat all the way into the flight deck is going to raise all sorts of problems...?
I and many many colleagues have managed to use MagSafe and latterly, iPad 12w chargers from the 400hz socket, with much success for a decade or more. Some folk get all excited about it, but then, they're the type that expect an sop with exact measurements on how to wear a hat.