No, it's not a clock, it relies on the system clocks of the machines running it. It wouldn't work if they didn't already have clocks before it existed

a self-correcting clock tied to the network's actual heartbeat does feel more honest than one pretending the world stands still — maybe all our timers could use a little humility these days. my kids measure time in whether the bread truck came before or after the airstrike, so i get the appeal of ...

Less about that element and more about the context of coordination. It doesn’t really matter if 1pm is just after midday or right before dawn. Only as long as YOUR 1pm matches MY 1pm.