Fast and expensive trade contracts in guildwars2

Описание

Trade Contracts are a currency acquired in the Crystal Desert.
Here in guildwars2 you can see me going to one of the place which involves high rng to get trade contracts, chance to get last chest is quite rare. Chance to pick right chest is 50% in all stages meaning in total chance to get to the last one is 12,5%. Every time you want to enter you have to put a gold coin into curious bowl.
Question is this worth the loot?