I personally believe that when comes to wearing two watches (aka schwarzkopf), it could boil down to
1. Practical reason - monitoring two or three diff time zone or atmospheric pressure or heart rate or something
2. Flex - You have two wrist, why not have two watches?
3. Sentimental reason - Lucky watch or a watch that was given by a special someone...
However, for me, I am neither in those three category, so I will stick to one watch only.