Reaction Images - Image #786,852

Probably because people watch it before work, since they won't lost track of time since Japan is in one time zone. In Japan, time has an elevated importance, and being on time for work is taken very seriously. So regardless of whether you're watching the station from Naha or Saitama or Sendai, the clock would be accurate (Unlike in the US, where there are a bunch of different time zones).