No, no they don't. I wish people who don't have a clue wouldn't try and state things with such authority.
Chromatic aberration isn't there to hide aliasing issues, it's there to add a flaw in the scene to stop it looking so clinical. Imperfections in a scene lead to the scene looking better, or closer to "perfect". It might not be the best effect to achieve this, but you're just making up reasons for why it's used.
Motion blur doesn't hide bad graphics, it can be used to hide lower frame rates, but that really isn't the intention behind it. Motion blur is there to simulate how our eyes work when viewing motion.
Depth of field isn't there to hide bad textures, it's there to simulate the way an eye or camera focuses, ie, the focal point. The closer your eye is to something, the more the background or peripherals are out of focus. Hold your finger up to your face, about 10cm from your nose. Focus on it and watch how everything else goes out of focus.