That is a recipe for unpredictable quilombo on certain N/S routes, which are in the same time zone for certain times of the year, and not, for other times.

MIA/SCL? Sometimes the time is the same, sometimes SCL is +1, sometimes SCL is +2.

SCL is on the Pacific and is east of MIA, on the Atlantic.

The flights are mostly N/S.

The customer would not ever quite know what to expect with this policy if one flew the route during various seasons.