I wonder what the thinking was behind the issue of a pocket watch as oppose to a wrist watch?

The only thing that immediately springs to mind for me is that a sniper could very easily avoid excessive movement when in a "lay up" as a pocket watch could be positioned line of sight rather than having to adjust position to view a wrist watch. Thinking about logically it would make sense for the sniper to have been issued both the pocket watch and a wrist watch at that period would it not?