This is a very personal question and depends on what kind of room you have and what kind of content you watch. If you're just watching free-to-air sports and the news, rear speakers aren't going to help you much. If you watch a lot of movies and TV shows on streaming services, play video games or watch some pay TV sports, then rear speakers will give you that full surround sound effect. The footsteps behind you, the crowd surrounding you, all the little things that immerse you more fully in the action. They aren't essential, but they are very nice to have.