I like to value things based on usefulness.
On my scale, a simple bowl is worth more than a party hat.
So, I reason, why buy a load of phats and trimmed or (g) armour (which has the same stats as normal armour), when you can buy seemingly infinite tools and supplies for skills.
Party hats are paper...why are they worth so damn much?!
You can lend out a party hat for money. What can you do with a bowl? Oh damn, seems like I forgot. I guess you can make a dish or something.
You buy phats because they will always be worth more later, and you buy trimmed armour for no other reason than lulz, it's barely worth anything compared to a party hat; where did that come from? lol f2p
Partyhats are discontinued. That's all that it takes for them to be awesome and worth stuffloads of money.