...and the bushes that support them are an integral part of the whole anti-roll thing, so if they are worn or shot, you get noise and/or crap suspension performance in corners.
When removed from particularly heavy vehicles (as I've seen done by dimwits in the 4x4 community) things can be extremely dangerous.....for example if you were to be braking hard into a corner, the amount of nose diving and body roll could easily be enough to flip you over, so their importance should never be underestimated; they are far more than the 'comfort' thing some people assume them to be.