Driving a car effectively is a two way thing. It's as much about your input - your stomping on the brake pedal, or your tugging wildly at the wheel - as it is the output of the car and all that it's telling you at any given point. It's what amounts to that near-indefinable 'seat of the pants' feeling that's integral to driving well - the way every bump of the road finds its way to your derriere, or how amidst all those vibrations you can tune into the individual knocks and scrapes. If you've ever been unfortunate enough to have experienced a major mechanical failure, you'll likely be familiar with how your car served up subtle warning signs well before things went truly south.
When translating all that into a racing game, there's only ever really one point of contact as opposed to the all-encompassing feel of being in a car, where those vibrations and sensations are translated through all that plastic and metal you're sitting in. With a racing game, it tends to just be the piece of plastic that's in your hand that does all the talking, which is what makes it such an important piece of any set-up.