Why is that vital? If a unidirectional bezel is knocked and unintentionally moved with a dive, it could only Screen an extended underwater time. That means the wearer will overestimate as an alternative to underestimate immersion time, and in conditions that require decompression stops, this can be a make-it-or-split-it element https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/