these outfits are “pointless” is basically undermining a major part of the runescape econemy. some people do live off clue scroll rewards and they get their money from people buying these “pointess” articles of clothing and the money they recieve from these rares they spend on other items (weapons, armors, resources, etc…) it keeps the value of the other items up in turn. RuneScape 2007 Gold. and as Indigo Red and bayba have stated if you buy these items further down the road they will be worth much more than they currently are worth.
take partyhats for example, they are not in an unlimited suppy eventually there will only be a few hundred left of each type and then the prices of said partyhats would be nearly as much as the christmas crackers from which they came, and as the author stated “For example, take the cash that is spent on black elegant clothing (1,720,200 gold-market price) and instead you could disburse that on various skills or even simple investing.”
this can be done by buying these rares and selling them when they are well above the price you bought them for. im not saying that everyone should buy rares, im just simply stating that these rares are a very large block at the base of the runescape econemy, and if no one were to buy them based on the views the author expressed that would in turn cause a catastrophic effect on the econemy.