The other use for timezones besides local midnight is the offset between geographical areas. UTC+2 or UTC+4. if I start work at 6 UTC and my buddy at 10 UTC, I know for scheduling purposes we are 4 hours shifted from each other. Whether you have to do math or not depends, but it is still a “timezone” by a different name. The only way to completely get rid of timezones is to ignore local time altogether.

Except when you have to work with people geographically separated. Trying to figure out when their work hours are UTC, and when yours are, so as to line it up. Boom, you’ve reinvented timezones by a different name.