Why is usually that significant? If a unidirectional bezel is knocked and unintentionally moved on the dive, it could only display an extended underwater time. That means the wearer will overestimate rather then underestimate immersion time, and in scenarios that need decompression stops, this can be a make-it-or-break-it issue that https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/