It's not "just a US Thing" as many countries around the world do move their clocks.
Conversely certain areas in the US do not.
St. Maartin does not. Areas that choose not to change are often located on the western edge of their respective time zone.
Even more confusing is when there are international time zones that are offset by 30 minutes.
I think the real key here is that Happy Hour will still start at the same time.