The most important feature of a pilot's watch is legibility, the hands and markers have to be easy to read at a glance. Another thing is the crown has to be oversized so it can easily be manipulated when wearing gloves. In other instances, there are situations where a chronograph might be needed when doing bombing runs to be able to time one location to another. Some watch manufacturers like Hanhart, IWC, Breitling, and Brequet manufactured watches strictly for military use, Hanhart made watches in small numbers manufactured for use by the Luftwaffe, and after the war made reparations to the French supplying their airforce with watches. Only much later did Hanhart start making watches for the public, Now most of us are not bombardiers, or fly German Stuckas and have no need for these types of watches we just think they look cool and like the old technology, the same could be said for dive watches how many people need a watch that is 30 bar, I did some diving and never had a need for even my 20 bar divers, they are just aethetically pleasing.
