But, they aren't begging for money.
They offer you an item that -you- don't really need, but you might want it. So they put it on the store, because they know some might want it. It's common business, there is -no- need to actually buy the mount. It's not like they allow you to have the mount for a few days, and then you pay. It is a choice, you sit on your chair, with your card and the store screen - and you can still refuse to buy it, just close the site.
Simple action really, I don't get why some people take this topic so ill. If you don't wish a sparkling pony, a golden dragon, a emo dragon (the color changing one) or anything of that sort, then you just decline the idea of buying it.
It is digital goods, created on the side or for a promotion, then someone at Blizzard sees this idea from an artist and go, "Lets use your design for something". They then share it with us, either ingame or via the store. It isn't gamebreaking or an advance, and no, 100% not "P2W" as some think it is.
It's digital pixels, ment to be unlocked via your account at the store. It's toys made to create interest.