In a business/formal context it would be normal to introduce yourself like this in the countries you've mentioned.
Do people introduce themselves like that in informal contexts in the USA? If so that's indeed a bit weird, and more a topic you would start talking about for small talk or if someone asked about it.
Depends on where. In big city yes
Americans don't usually have friends. Just "contacts". Working age "parties" are often just cloaked networking events.
I would find it strange if someone introduced themselves to me with their business title. I sometimes ask "what do you do for a living?" as small talk, but that's solicited.