The geometry goes much further than checking the wheels are pointing in the same direction. The handling of a car can be altered hugely with very subtle changed to the tracking, both front and rear. Measuring what you have and adjusting it in accordance with what you need is essential.
Geometry also includes castor angles and camber settings. More front castor will affect the camber as the wheel rotates through lock. This gives less steering feedback but a better turn in. Rear castor angles will affect the traction during suspension travel. Camber will affect the tyres grip as it is subjected to side loads, when cornering. However it must not be overlooked that increased (negative) camber will reduce traction and braking in a straight line. Like everything in life there is a compromise and that is what we aim to find.