Wheel Balancing is to ensure that the when the wheel is spinning its weight is equally distributed, if the weight of the wheel isn’t equally distributed this is called “out of balance” and you would feel a vibration/shake while driving at speed of approximately 40mph and above.
If you are feeling vibration at lower speeds than 40mph its possible that one of you tyres are out of shape or another mechanical problem with the vehicle.
If your wheel balance is out it can cause premature wear on your suspension parts.