I doubt that it is popular with the actual users, only with the company that they work for. When I had a company issued AMEX card the damn thing was practically useless. In fact even in the US there were plenty of places that wouldn't accept it.

I use an Amex as my primary and preferred personal card, and legitimately can't remember any place in the US where it wasn't accepted.

In Europe it is pretty hit or miss though, unfortunately.

AMEX cards are being used by both large and small businesses. It's accepted by hotels, restaurants, airlines, suppliers, utilities, etc... Small shops are of little importance.

> Small shops are of little importance.

Unless they happen to be selling something you want to buy.