Not really true either, it’s often called military time as a colloquialism because people will know what you mean and it strangely feels more normal/easier to say than “Twenty Four Hour Clock.”
EDIT: Also for the nomenclature, I personally still refer to time in the 12 hr format when talking, but if for some reason I have to say the 24 hr format it depends on the number. I would also say fifteen thirty for 15:30, but I would say fifteen hundred for 15:00.











No, it’s just a familiarity thing and not even rare. It’s like switching between metric and imperial units, if you’re used to seeing something in one format it can be jarring to switch it in your head at a moments notice. A lot of people in the US use 24 hr time if they have a job relating to documentation or if their working hours can cause confusion.
For example, I have a client that has to document received material and they are open from 04:00 - 22:00. They use the 24 hr format because it is common to receive material at both 04:00 and 16:00 and having to make an extra column to type am or pm on their logs is stupid and is just another opportunity to make a mistake.
It’s really not a big deal to anyone, if you get a job that uses it then you switch your phone and within a week or two it’s second nature. Every blue moon someone will notice that all your clocks are set to a 24 hr clock and someone might ask why or what you do to need it, but that’s it.