All other school dispels cost two pips to cast making them not worth the pips most of the time to use unless you are of their school. The storm school dispel only costs one pip to use which means that everyone pretty much uses it against storm school without any real pip cost at all. Storm already struggles to cast against a vast number of shields and is typically the most likely to be hit with beguile, allowing everyone to have a single pip dispel against storm school is taking things a bit far, expecially when one pip dispels don't exist against other schools.
Are you sure your not confused with the treasure dispels, because the eye of bartleby dispels cost 1 pip, as opposed to 2 pips like the normal treasures and regular dispels.
sorry, when I wrote this I was referring to the treasure cards that are very cheaply boughten at the bazaar ... for some reason one of them cost only one pip to cast
Perhaps you should pay attention. Dissipate is a 2-pip card. The only 1-pip version of Dissipate is from the Treasure Card set (otherwise the normal Dissipate treasure card is 2-pip), which you can purchase as an individual treasure card from the bazaar.
Although you're right and this is unfair...so's life. Sorry to be so callous, but I'm pretty sure they're not changing the amount of pips needed for spells any time soon, just like they're not adding a Balance shield or an interaction to use furniture.