The pathological case with scheduling is: It's 2015. You live in NYC. Your pal in Santiago, Chile says "hey next time you're here let's hang out." You say "great, I have a business trip there next April. Let's have dinner at 7pm on the 15th." They agree. You enter it into your calendar. If you store it as UTC, you're going to show up to dinner at the wrong time—the DST rules changed in between when you talked and when you expected dinner to happen. If you'd stored it as a local time with tzdb name America/Santiago you'd be there at the correct local time.