[time-nuts] purpose of time of day display units

[Ruslan Nabioullin]

Hi, looking at pictures of various time metrology equipment setups for 
best practices and inspiration, I have commonly seen time of day display 
unit(s) installed in racks containing processing or time transfer 
equipment, e.g., 
http://www.xyht.com/wp-content/uploads/2015/05/Powers_Master_Clock.jpg. 
All that these units do is merely display the time of day and sometimes 
the date, typically by means of seven segment LED displays, of the time 
code inputted to them (typically IRIG-B, I'm guessing).  Any ideas why 
such a unit is necessary when one can simply look at the time displayed 
by timing receivers and time code generators (and even some standards), 
and the interface of some fusor, defined in this context as a system 
which performs timing data fusion (by implementing a paper clock or a 
more primitive algorithm) and timekeeping, either by means of a direct 
shell, or via something like NTP?

Thanks in advance,
Ruslan