Well ten minutes by car, plus find parking, plus pay for parking. Lots of people myself included, living right next to a Luas stop don't have a car, so the 40+ euro return taxi trip to sandyford adds on to your punt.
There was a girl a stones throw from my place which I used twice. Very handy just going down in the lift, crossing the courtyard and ta-dah! There she is.
As another poster said, it depends on short term rentals.