I used to dive a lot, like at least 2,3 dives a week for many years, and I will say Rolex has a history with divers, especially pro diver that no other brand will ever have. I have seen tons op divers dive with reflex as backup, I don’t think I have ever met someone with a seas master. Of course, I never made a point to check out other people watch when diving, and it is possible that I mostly noticed people with Rolex. Seiko is also a popular brand you see a lot around divers. Keep in mind that divers rely primarily on their dive computers. A mechanical Watch is really there for back up.