Originally Posted by DJosef
That's because you're German.
(I just checked it on your profile.)
This kind of garment just doesn't have a history in Europe outside the navy. Even in Britain it's very specific to sailing or yachting... So I guess it can be considered an Americana.
Very true, while living in the US I have seen navy blazers with brass buttons all the time. In some regions it even seems to be an acceptable substitute for lounge suits in business settings, e.g. in the Souteast, my observation was that often navy blazer with brass buttons + khaki trousers + blue OCBD shirt ( + tie ) = typical office worker uniform. Therefore, a navy blazer is very versatile in the US as it covers the spectrum from casual to business settings.
In Europe and also as far as I can say in Asia, brass buttons are rare and will provoke questions such as "where is the ship, skipper". Still the navy sport coat with horn, MOP and in the majority of the cases black plastic buttons is popular, but not really acceptable in more formal business settings.