Why collect Pins?  Well, it's a lot more reasonable hobby than collecting cels or even trading cards.  Besides you can find
all your Anime favorites.

There's always room for more.

It's not so important to have a complete set. 

My first pins were the Ranma.  I got 3 of these at Dragon Con some years back,
for 25 cents a piece.  Needless to say, collecting is more popular now. 
(Still for a new pin the price is usually 2-4 dollars.  Not too bad.)

Although I would like to have all of the round Gundam Wing on the top of this board.  (Unfortunately this was all there were, and there would be no more.)  =sigh=

They don't scan particularly well though.  ^_^;