That watch movement is graduated in minutes and seconds in the Decimal Minute Second System. It also has a standard hour, minute, second face.

It was used by aircraft navigators flying long distances and by astronomers in their repeated observation of a particular spot in the sky. Both uses were before the advent of computers and the GPS system. That particular watch work was installed in the plexiglas holder for mounting on a plot board on the aircraft navigator's desk. It was found that navigators made far fewer mistakes while using the DMS system in plotting position to position of the aircraft.

An aside; there were many efforts by mainly so called scientist way back in history to change the 24 hour, 60 minute, 60 second measurement system of time. Most wanted to decimalize the hours, minutes and seconds. One or two actually wanted to decimalize the year. None of these systems were ever very popular. The very powerful religions of the time didn't want and wouldn't allow the change.