I understand it has something to do with Europe and in particular, the French.
I dislike using the term, four syllables for a unit seems excessive and we're not even allowed to use hPa as an alternative. That said, I do use it as a pilot and as a/g operator. I agree re safety, but hey ho. Is saying it more or less safe than not specifying units at all? The only reason we use units below 1000 is because of the Americans who might get confused...