If you're using a rifle indoors, maneuverability is already an issue. A bayonet makes it worse.
I am going way out on a limb here, but the only advantage I can think of might be that it could help in weapon retention. If someone were to try to grab your rifle from the side, getting a hold of a sharp blade may encourage them to let go. However, there's probably better tactics to use so you can avoid that altogether.
If your using a rifle for home defense and the problem persists, you probably have a situation that a bayonet won't solve anyway.