Sega used this in their pioneering MMO from ~1999, Phantasy Star Online. “Beat Time”. The idea was to help you coordinate meeting times with people regardless of time zone. The problem was we had to convert it to regular time to have any idea when 725 beats was or how long 150 beats from now was.
Eve Online have something similar too. The Eve time is just Reykjavik time, which makes conversion easier. I used to have a clock on my phone screen to show Reykjavik time to remind me of the event time with my space friends.