Why do the community needs a receiver to learn these memories of the outside world since they are rarely going to use it anyways

Jonas lives in a highly structured, organized, and safe community, which is completely protected from the outside world known as Elsewhere. Jonas's community has been dramatically altered over the years until the entire environment has become safe, comfortable, and controlled. The community abides by the concept of Sameness, which essentially prevents individuals from acting independently and experiencing the world from an authentic, genuine point of view. For example, Jonas is one of the few people in his community that has the ability to see in color, and the Giver is one of the few people who can actually hear music. The complete isolation, altered environment, and lack of perspective result in an ignorant society which does not remember what life was like before Sameness.
The Receiver of Memory's assignment is to keep all the memories of the past, particularly difficult human experiences, and to consult the Committee of Elders on significant decisions that require wisdom. Since the Receiver of Memory is the only citizen in the community with knowledge of the past, they are revered in their society, and they provide insight into difficult/significant community decisions. Even though the Receiver of Memory is rarely consulted, their opinion still matters, and their main job is to protect the citizens from experiencing the difficult memories of the past. Since the Receiver of Memory keeps all of the painful memories, the citizens can experience a completely comfortable life.