Like Carcassonne, it is a great place to be at night, once the masses have departed; to wander lanes lit dimly, slipping through the shadows to watch the moon rise over waters moved by its influence.
You find an inner peace then that may just be the contrast with the brouhaha of the day, or something more spiritual and calming, or the simple by-product of holiday escapism.
Then, when the tide comes in and engulfs the land, the island state returns and, for a time, there is a keen sense of impregnability… a sense of isolation…a sense of place.
Maybe that is what Mont St-Michel is about.
Architecturally, it’s still a mess.