Santiago and Buenos Aires are often in the same timezone but differ during DST. Chile observes DST (September-April) while Argentina does not. During Chilean summer, Santiago is 1 hour ahead of Buenos Aires.
Both capitals are major business hubs on South America's Pacific and Atlantic coasts respectively.
Business hours align well! Even during DST differences, the 1-hour offset is easy to manage. 9:00 AM Santiago is 8:00 AM or 9:00 AM Buenos Aires depending on DST.
Santiago and Buenos Aires are connected by frequent 2-hour flights across the Andes. LATAM operates the busy route multiple times daily.