I am not someone who really enjoys discussions about definitions, but I'll jump in too.
The emphasis on Africa suprises me. I thought that at least the Americas, but also Asia would be included in the definition.
Could it be that because most trade beads 'come back' to us through African dealers, that we are geared towards thinking that trade beads are 'made for Africa'.
I am guessing that it is also about quantity, but still.....

Also, about the use of beads as money. From what I understood, beads were used for bartering and trading, but not as such substituted money. There are some specific exceptions to this, but I think most countries at the time of the heyday of the trade in beads (1880-1930, I think) had some type of currency? Mostly from the nations that colonized them?
From an article by Peter Francis, I also understood that the Manhattan story of it being traded for beads is also somewhat of a myth. Which is a shame, because it is such a cool story...... ;-)