This group seems to be both revered and feared in the universe of "Dune."
Like all powerful group with significant influence, for centuries, they've been building coalitions, with a well-balanced use of common benefits and fear.
They also have some powers some people see as "magical"1:
A powerful social, religious, and political force, the Bene Gesserit is described as an exclusive sisterhood whose members train their bodies and minds through years of physical and mental conditioning to obtain superhuman powers and abilities that seem magical to outsiders2. Bene Gesserit
The ultimate goal of the Bene Gesserit Sisterhood, up to the end of the novel Dune, is the creation of a male Bene Gesserit they call the Kwisatz Haderach. They intend to achieve this superbeing through a massive human breeding program, which they have conducted for countless generations; using careful manipulations of relationships and breeding sisters to "collect" key genes, the Bene Gesserit have controlled and finessed bloodlines through the ages. Also called "the one who can be two places simultaneously" or "the one who can be many places at once", the Kwisatz Haderach (defined by Herbert as "The Shortening of the Way"), with mental powers that would bridge space and time and access to both male and female lines in Other Memory, will be an overt figure in the Bene Gesserit's manipulations and thrust upon the universe as a messiah. Bene Gesserit goals & strategies
Often mistaken for a religious order, the Bene Gesserit (also known as the Sisterhood) is an ancient organization of female spies, theologians, and scientists whose mystic origins and enhanced physical and mental prowess make their existence integral to societal order.
The Bene Gesserit resorted to influencing politics from the background before Paul Atreides assumed leadership of House Atreides. They preferred to stay in this role for over a millennium. The group succeeded at placing agents in all the important imperial courts and Houses to oversee major negotiations. Dune: Bene Gesserit Explained - History, Origins & Powers
1. Regardless of their ranks in the organization's hierarchy, each member can control every muscle and fiber of their body as they are masters in the disciplines of prana (breath) and bindu (muscles). This allows the members to simultaneously remain motionless and bend the last joint of their little toe, and deliver blows with extreme physical force. Their powers are such that the Bene Gesserit martial arts are not even centered on armed strikes. Instead, they can resort to unarmed attacks resulting in destructive physical blows and movement that's extremely fast and precise. This fighting style is usually referred to as "the weirding way" in the world of Dune.
2. The Voice is another major power that allows the Bene Gesserit to manipulate people by giving them orders in particular sound frequencies that only they themselves are resistant to. Then, the Bene Gesserit members trained as Truthsayers are particularly adept at analyzing people's speech and physical mannerisms to determine whether they're lying or speaking the truth. All the Sisters have significant and impressive control over their own bodies and fertility levels. They are able to alter their metabolism to even render poisonous substances harmless. These physical abilities make them integral in the Houses as poison tasters and concubines.