(Wikipedia) Totalitarianism is a form of government and a political system that prohibits all opposition parties, outlaws individual and group opposition to the state and its claims, and exercises an extremely high if not complete degree of control and regulation over public and private life. It is regarded as the most extreme and complete form of authoritarianism.
In Dune, it was used for thousands of years to build up a desire to spread, to instill a lasting distrust of leaders who would implement it, and to control the genetic trajectory of humanity in a way that would let them survive a foreseen existential threat.
In the real world, the benefits of it are for the ruler, not the populace.