Finance/insurance generally sticks to dates instead of timestamps for most of its data, especially since the effective date might be different from the timestam

Finance/insurance generally sticks to dates instead of timestamps for most of its data, especially since the effective date might be different from the timestamp date (e.g. a weekend or night transaction having the value date for interest calculations set to the next business day; but you also might have backdated transactions caused by various corrections). Timestamps and timezones are used for logs and auditing, but for settling money it's generally considered that the thing that matters is at the granularity of a whole date. Of course there are things like HFT where precise time matters a lot, but there you don't schedule things years in advance, all the long-term things like mortgage schedules and insurance terms simply ignore time and timezones.