P.S.: I'm not sure if this is contradicted somewhere in the game, but having the prism would also work as a fail-safe for Gortash in case either the Absolute, or the other chosen betray him. Given he believes that the prism has an area effect, he could keep the prism under his pillow to avoid getting dominated. Or, he could build some sort of tadpoled but loyal bodyguard, Steelwatch commandos or just upgrade the existing Steelwatch. At the price of a bunch of replaceable mind flayers led by a former rival in crime that is motive, means and opportunity.
My memory is also a bit fuzzy on whether the tadpoles Tav and the gang received were especially special tadpoles, bred for the prism bearers, or not.
