While I do agree $29.99 wouldn't go over with the masses, I believe there are players (including myself) who would be willing to pay decent sums of money for vanity items.
And while I agree we'd be the minority. I do believe there are those who will throw there money at Square Enix for in-game items, and Square Enix knows this.
While this does not justify the argument any more it's happened before in a previous MMO they've had...
FFXI had items priced highly (although they did come with items, many players bought it simply for the in-game item)
Tidal Talisment
(Might I add this was released during Einherjar prime days and many end game players bought it simply for the quick teleport to Nashamu)
Harpscord
So again, While I don't disagree with asking for the ability to buy the items alone, Square Enix does have evidence to show players will spend decent sums of money ($30+) even when it is attached to a physical item, many bought it simply for the in-game item rather than the physical item and the choice to buy them separately was not an option.