It’s extremely common in Europe. I regularly get messages with “15h”, “22h”, etc, but spoken is a bit of a mixed bag, you can usually use 12 hour time and know if it’s AM/PM from context, but sometimes you need to be specific.
Though the weirdest thing I’ve had to learn in Germany about time is, near where I live it’s common to say “one/three quarters [hour]”, instead of “quarter past/to [hour]”, so 10:15 is “one quarter 11”, and 10:45 is “three quarters 11”. It makes a little more sense when you know that “half 11” mean “half to 11”, not “half past” like is typical in English.
Sure, but it has made RAM more expensive for everyone, not just those who want to run LLMs.