I'm sorry, but who notices and who cares about a fifth of a millionth of a second?
You will when the satnav in your car tells you you're somewhere that you are not. Or when your bank disagrees with the timing of your money on payday and rejects it. We might fret about 20 s/d on our watches but we rely heavily on these atomic clocks for "civilised" life. Luckily the clock(s) in Boulder are not the only ones.
It's a cool topic, because time does pass differently sometimes, but especially in different places. I heard an interview where these time scientists (phycisists) are excited about testing their theories of time passage on Mars. I think it is 400 milliseconds slower per day or something? When you consider future galactic travel, getting computers and navigation synced up is a big deal.