[Question] Why is there a downward pointing triangle at the 12 position at some watches?

I know pilot watches has the upward pointing triangle to orientate the watch in the dark, but why the downwards pointing on many divers and field watches?

does it have a functional explanation or is it just a design playing on the pilot watch design? or is it unrelated to the pilot watch?

example:


edit: field pilot watch design? or is it unrelated to the field pilot watch?