Such item is a disaster, I already experience a cash shop item like jump level coupon or even max level for only few hours from the different game private server with a thousand percent exp boost and many more stuff, now to day those servers are like extinct dinosaurs.
Did you even wonder why official servers despite of having a very bad Exp/Drop they are still alive today and even more populated compare to a newly beta private server version of them that only last for 2-2.5 years?
(i don't have any forte & any talent of giving an idea due to my very bad English grammar but ill try)
its because official servers are capable of balancing & manipulating the "want & needs" of a players. Humans are naturally not repulsive to change, so if you slow down, regulate or manipulate this change the can stay much more longer compare to speeding up the change what most typical mistake done by private servers. if these players experience the changes or everything in just a blink of the eye tomorrow they're gone.