Everyone makes good points but the point is that Square is a business first and foremost and they decided that they can make a profit by selling things in a cash shop. These cash shop items are optional and don't affect core gameplay in any way, they are just for show.

I'm pretty sure that they would have carefully calculated an algorithm that determines the price that they set these items at. There's going to be a smooth spot that makes the most money possible. Why price something lower with more people buying it when you earn less than what you could get if you price higher but less people buy it? That makes no logical sense in terms of business to sell it at a lower price that gets you less profit.

It just happens that there are enough people are willing to buy it at the current rate that it doesn't matter that they're selling less. It is digital goods after all, they don't run out of those. Physical stores have stock and would like to sell them all.

As for me, I have no interest in them, so I won't buy it like I did the play dead emote (which I use all the time).
My friend bought it because he's a sucker for that style and has more money than I do.