Comment by crazygringo a day ago
For storing actual moments in physical time (especially past events), and where the time zone is irrelevant, for sure.
But for storing future events that are tied to a time zone, you need the string with time zone. Otherwise when time zone definitions change, your time will become wrong.
As I said, because time zone definitions change.
If daylight savings time gets cancelled by legislation, then the event happening at noon two summers from now, you will still probably want to happen at noon -- the new noon.
But changes to timezones don't apply retroactively. At least not in this universe!
The cultural rules tend to be more important when describing future events, where the “human friendly” description is what really defines it.
When describing past events, it’s often most precise to describe the literal universe time that it happened.
Obviously these are just generalities, whether you choose one strategy or another depends on the specific use case.
Units of time can also change. It's possible that a day of 10 hours of 100 minutes could be legislated. Not likely, but possible.
UTC is pretty stable though. I recall they will obsolete leap seconds somewhere in the next 10 years