Question

how was feudalism beneficial

Answer 1

Feudalism was good because: 1. It offered protection to all the common people, because they were being watched and protected by the knights. 2. The knights got money from the lord in exchange for protection over the lord's manor. 3. The lords got protection in exchange from the knights (which is called a fief)
Those are just some of the reasons

Answer 2

Feudalism was beneficial because it created a larger military force. With knights constantly pledging their resources and abilities to many different lords, there was a huge military force, even though sometimes two of their lords would fight against each other and they would have to choose sides.