No idea really. I made it quickly this morning, and I'm trying it out today. It does make it easier to see whether a bunch of commands were performed at roughly the same time than a digital display.
Your advantage unfortunately obscures other useful information.
My [zsh] prompt displays the exact time down to the second on its own line. I just scan up looking at the time to see if the hours match or minutes... But I still have the ability to know if one was 3 minutes 33 seconds or one was 27 minutes 10 seconds within that hour/half hour.