If that's what floats your boat then do it, just saying why I wouldn't. I suppose you envision this as you would lower the car when driving around town and then raise it up to park it in your garage? Whatever makes your car useful and brings you happiness is no skin off my back.
People spend thousands of dollars to shed 5 lbs off a car, if we're talking about a serious performance machine adding 20 lbs for convenience doesn't make sense to me. I mean, I do understand your angle. But if I'm going to drop the money on serious aero modifications and take full advantage of it with a non-streetable ride height, there are likely several other compromises to driving on the street such as tire choice, alignment, a very stiff suspension, chucking out all the amenities for weight savings etc.
Manually adjusting the ride height would be a minor inconvenience well worth the 20 lb savings given all the other things that would go along with what is included in taking full advantage of a low ride height imo. As for a pure race machine that the most difficult part of the day is getting on and off a trailer, ramps and lifts exist.
Edit: Indy cars carry a pneumatic jacking system on board to aid in pit stops, and I believe many enduro cars do as well (LeMans, Rolex etc.) so it's not unprecedented but I guarantee you they would ditch it in an instant for the few lbs weight savings and send a dedicated jackman or two over the wall like F1 or NASCAR.[/url]