Strange dating customs around the world
It is one of the old teachings of Confucianism  and reveals its inclination toward conservatism. It was still practised in the Dutch and French navies until Instead of being a manservant to Strange or more recently bodyguard like in the comics, Wong is a Drill Sergeant Nasty for the Ancient One's disciples, a master of sorcery and head librarian.
A gesture of intended friendship may also be seen in forms of salutes by armed vessels. It has never been considered advisable to allow civilian tradesmen onboard.