Both scenarios require learning, only one scenario requires constant back-and-forth conversion, which in turn introduces opportunities for mistakes and confusio

Both scenarios require learning, only one scenario requires constant back-and-forth conversion, which in turn introduces opportunities for mistakes and confusion. Here is another example: I schedule a meeting with my co-worker in London. I say "how about 10am your time?" This is because I know he is X hours behind my timezone because I've learned that fact. He agrees and I show up an hour late because I forgot about DST and that he is only X-1 hours behind now. If we both coordinated around UTC, he would've said "actually 11 is better for me" and I would've showed up an hour earlier.