Indeed, macOS supports something similar. The notification center has a World Clock widget. I've got friends in Illinois, India and Australia, and it's incredibly useful to have a couple of clocks right there.
When I was at Sun, somebody hacked up a version of Michael Power's classic NeWS "Glass Clock" tool (that shaped the window so that it only showed the hands and the 12 tick marks, so its face was transparent and mouse clicks passed through it), so it ran setuid root in order to call stime() to set the operating system's time, which it let you easily do by simply dragging the hands around the face, just like a real clock! ("Temporal Direct Manipulation"!)
% Glass is an implementation of a NeWS clock that I wrote to
% experiment with shaped canvases. The clock is shaped like the
% the hands and tick marks thereby allowing you to "see through'
% the face to whatever lies behind. Because of the bug concerning
% stroking a canvas path the face must redraw every time it is
% updated (gross).
As it turns out, it REALLY SUCKS to have a clock that made it so easy to accidentally change the time on your workstation! The way the glass clock could float unobtrusively above your other windows, it was really easy to accidentally hit the hour or minute hand with the mouse and move it without noticing, then you'd miss meetings because your entire workstation would have the wrong time! Unless you were running it over the network on a different server, then you'd change the time for everybody else using that server, so they would miss their meetings too!