With WWV and a older-style shortwave receiver, the public has the ability to set a stopwatch or similar device to sub-second accuracy. More importantly, a person who isn't a time lord can be reasonably certain they have accomplished this task correctly.
With any other device I can think of, there is a lot of computing equipment serving as an intermediary between the radio signal (or the internal clock set by NTP) and the time display. This intermediary computing consumes a non-obvious amount of time that non-time-lords are ill-equipped to evaluate. Therefore such devices cannot be relied upon to display time to sub-second accuracy. Such unreliable devices include personal computers (whether Linux, MacOS, or Windows), consumer "atomic clocks", consumer GPS devices, cell phones, etc. A less obvious instance of an unreliable computer intermediary are some of the more recent short wave receivers which perform digital signal processing, which may occur on the RF signal, the intermediate signal, or the audio signal. People with a practical need for sub-second accuracy are navigators and land surveyors obtaining azimuth measurements by observations of celestial bodies, among others. The number of people who can make a formal statement that the time kept by a particular clock is traceable to national standards will be drastically reduced, because the number of people who have, and know how to use, a shortwave receiver is vastly greater than the number of people who have a clock steered to GPS, and are capable of making a formal statement about the accuracy of the GPS-steered clock. WWV can also be played to the public to directly demonstrate to that polling places are being opened and closed at the correct times. Computer displays and cell phone displays may not be persuasive to the public due to the extensive publicity about Russian hacking and other illegal manipulation of computers and related services. I'm an election official. I wonder how it will go over if, during the 2020 US presidential election, I turn a voter away because the time to close the polls has just passed, and CHU is playing in the background. _______________________________________________ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs