There seems to be this myth that coil overs are some kind of magic suspension item that will transform the handling of any car, and will always give a hard ride. This is due to the cheap (and not so cheap) crap suspension kits that come with springs and damping far too heavy for road use.
A McPherson strut i.e. the bit supporting most cars on the road is a "coil over", i.e. it has a coil over the damper. Aftermarket coil-overs use exactly the same principal, the differences being that the spring seats are usually adjustable, and they take standard sized springs which can easily be bought in different lengths and rates. The dampers are usually adjustable, or can be valved for as specific application but decent inserts for McPherson struts often provide this feature anyway. The whole point of coil-overs is to provide lots of scope for adjustment to suit the use of the car, so it's hardly surprising that one-size-fits-all coil-over kits are often a massive compromise.