*warning, the following information is mostly made up; it is only fact in the innermost circles of strange imagination*
Flips, 2X2 cardboard, capsules, slabs, boards. All of these and many more serve the supreme and sole purpose of containing our prized coins. But, for some indecipherable reason, no history book I've ever come across explains their origination. Resolving to enlighten my fellow humans of this grievous error, I immediately began research (well... technically I went to that concert first, then I had this vacation...). After concluding that WackyPatio had nothing useful to say on the subject, I began digging in my front yard... then realized after a discussion with my mother that it really would be more likely I'd find what I wanted if I filled up every single hole I had dug, and relocate my irritating, dirty activities to the local forest. Eventually though, ten feet down, I found it. A document detailing the early development of coin holders! While it was all in the ancient language of Geek (as in coin geek), I made quick use of the Ro-cent-a Stone, and discovered the following;
In the early days, collectors, who at the time by the way had not invented grading (that would come with the very advanced Ro-Notes Empire), struggled to keep their coins in one place. Constantly these prized numismatic specimens would roll all over the place (which is why ancient coins are never perfectly round by the way; rough surfaces caused uneven wear in the rim, which lead to more uneven rolling, hence really un-round coins). Sure, they could have been laid out flat, but remember the Geeks (again, as in coin geek), were a very philosophical sort; to only view one side of the coin is to be close-minded. Then, after wrapping up some insignificant works of literature, something like Nickel-mean Ethics, Ari-dollar had a light bulb moment. A big one. He remembered that people who were squares never wanted the good times to roll on. So why not create square holders so the coins wouldn't roll on? After several concept designs, one of which had the issue of entirely covering the coin from view, another of containing too little PVC (the local government, who were heavily invested in PVC stock, required it), Ari-dollar finally solved the problem of rolling coins with the first coin holder.