Dropping your car onto the floor is a fairly good anti theft device as it makes it very difficult to move, also in my case i dont have a dropped kerb to get onto my driveway so being able to move it up a few inches will help, besides, who says it has to be usefull?
Spoilers that pop up up at 70mph, alloy wheels, chrome bumper inserts or 3 pointed chrome stars are not usefull but we like those things, cant go through life judging stuff on how usefull it is, its fine to not like stuff, but you cant dismiss things based on usefullness or the whole art world becomes pointless, these things give some of us pleasure while others are more interested in gadgets or speed.