Why is significant? If a unidirectional bezel is knocked and accidentally moved on a dive, it could only Show a longer underwater time. That means the wearer will overestimate as opposed to underestimate immersion time, As well as in scenarios that require decompression stops, This may be a make-it-or-crack-it factor https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/