What could possibly be cheaper and more reliable in a timekeeping role than a battery powered watch with some moderate level of water resistance(shower, washing hands, surface swim) selling for less than $100? A battery powered diver's watch, completely waterproof and functional at depths far beyond sport diving range can be had for less than $200. Wristwatches require no pockets, and are extremely utilitarian. In fact, their descent from the demands of WW1 trench warfare, and their continuing use by elite military units suggests that they are still held in high regard by those capable of easily traslating analog displays and requiring quick and easy accesss to a timekeeping device that requires no special handling or storage.
There are very expensive (and often not very rugged and reliable) dive computers that can be worn on the wrist, but doing so when not in a diving situation puts one in the same category as a scuba instructor I once knew who walked around with one of those big old diving knives strapped to his leg whenever he wore shorts or a bathing suit within several miles of the ocean or when he was in his dive shop. These days, when overweight office workers barely able to swim are able to proudly display a certification card there are (I hope) few people so spectacularly fatuous, so pathetically in need of disguising the interior Walter Mitty, that they seek to impress people through such infantile displays. There are a few wandering around out there, though.
I have a dive computer, and I use it. Anyone who cannot safely plan a dive without one should not be certified.