While this is partly true - perfect ergonomics for cold water would probably be imperfect in the tropics. Oversized dials and knobs would be clumsy and the sharp edges on dials (needed to grip with numb fingers and 7mm gloves/mitts) are not comfortable when you soft fingers (without gloves) after 5-6 hours of underwater photography on a warm day in the tropics.
At least you now know what to look at in the test.
p.s. More controversially, the same is true of divers. I have lost count of the number of British divers who think that because they can dive in the UK - it means they don't need to learn anything to dive in the tropics.
I absolutely agree, the currents can be very different in the tropic and in the tropics a cold water diver looses the sense of depth, we are used to see the surface at 8 mts, but in the tropics you can see the surface at 30 mts or more and there is more light, giving you a false sense of security and that can be dangerous.