For communicating internationally, it's much easier to think "it's 10am there, what does that mean in terms of whether this person I know is likely to be asleep

For communicating internationally, it's much easier to think "it's 10am there, what does that mean in terms of whether this person I know is likely to be asleep/working/etc" than to think "it's 10pm here" then try to remember what's going on at the same-named 10pm on the other side of the world.