Cleopatra Was Extremely Well Educated
It was likely that education that helped her in a number of different ways, including helping her to draw in new allies (aside from her lovers) and to turn her charm into something of a weapon. She wasn't the characteristic beauty, but she was intelligent and even wrote her own books.
In fact, Cleopatra's books were on things like science and philosophy. She was good at conversing with scholars and was well-versed in mathematics, chemistry, and philosophy. So she didn't need to be just a pretty face.
