It also fits in well with Kylo Ren’s character. He turned to the dark side primarily because he believed he was owed a place in the galaxy because of his lineage (contrast with Rey also wanting a lineage to place herself in the galaxy, except she makes something of herself because she didn’t have one and had to). He could be an incredibly prized possession by the First Order because he’s a relative of Vader, Luke, Leia, and Han. They give him a place in the galaxy and he gives them one too.