For years I've had `gc` in my terminal mapped to `TZ=UTC0 git commit` for exactly this reason. No need to change system times or git settings. (though perhaps a better way in global config?)
It's not even for nefarious reasons. I travel a lot, and don't like leaking my travel itinerary on public repos.
It not only sets the timezone to UTC, but also sets the time to 00:00. So my commits will only have date information. I think only saving the date permanently in the git commit is good enough. No need to leak the precise time I made commits.
Same. My phone automatically changes, and I'll manually change my watch, but when I travel, I leave my laptop in my home time zone. Part of it is I just can't be bothered, and part of it is I want an easy way to know what time it is at home without having to fiddle with a world clock.
Time zone is purely a displayed time consideration. I'm not bothered that the display time on my computer is different from the time zone I'm actually in.
It's not even for nefarious reasons. I travel a lot, and don't like leaking my travel itinerary on public repos.