The epilogue of Red Dead Redemption 2 is a crucial part of the story, as it serves to round out the journey of main protagonist Arthur Morgan. The epilogue helps to tie up loose ends and gives us a glimpse into the future of the characters and the state of the world they live in.
Firstly, the epilogue provides closure to Arthur Morgan's story, as it's a reflection of how far he's come throughout the main story. By the end of the main story, Arthur is dying of tuberculosis, but despite his ailing state, he still has made a significant impact on the world and the future of the Van der Linde gang. The epilogue allows us to follow John Marston as he struggles to keep the legacy of Arthur Morgan alive, and we also get to see some of Arthur's old friends and allies helping him out.
Secondly, the epilogue further develops the world of Red Dead Redemption 2 and allows us to learn more about the characters and their lives after the main story. We get to see what John Marston is up to, and his relationship with his family and the older characters. We also get to meet some of the new characters that live in the post-RDR2 era, and those characters help shape the narrative, as well as adding more detail to the world.
Overall, the epilogue in Red Dead Redemption 2 is a great way to cap off the story and give it a proper ending. It is an important addition to the game and serves to bring the Van der Linde gang's story to a satisfying conclusion. It's a great way to get a better understanding of the world and its characters, as well as providing a nice way to wind down the main story.