While the paddle float was devised as a way to improvise an outrigger for self-rescue, its best use, in my opinion, is as an aid to a reentry and roll. Once the rudimentary principles of a roll are mastered, a reentry and roll with a paddle float can offer a reliable self-rescue, even though rolling without the float might still be elusive.
For a reentry, flip the kayak upright, float yourself alongside the kayak facing the bow, and grasp the paddle against the far side of your cockpit so that it extends out at right angles past you with the float as far from the side as possible. Grip the near side of your cockpit with your other hand. Lie back in the water. Hold your breath and swing your feet into the cockpit between your hands. Still gripping both sides of the cockpit, wriggle yourself into your seat, and with your feet on the foot braces, grip firmly with your knees. Now grasp the paddle shaft with both hands and gently pull down against the buoyancy of the paddle float until your head reaches the surface and you can breathe and see what you are doing. Relax now in this position. Finish your roll by pulling down on the paddle with the hand closest to the paddle float, pushing your head down toward the water and flicking with your hips to right the kayak. When the kayak is upright, bring your head inboard close over the deck. Maintain your balance with the aid of the paddle float by gripping it tightly across the cockpit coaming. As with the previous paddle float self-rescue, in windy conditions or in waves or surf, enter from the side the waves are approaching from so that you are bracing on the correct side once you are upright.
If you practice the reentry and roll with a paddle float and find it straightforward, try deflating the float a little. The less buoyancy you need in the float, the more efficient your hip flick is becoming. Ultimately you might aim to be able to self-rescue without a float, but then you can still carry the float as a back-up in case you need it sometime.
Of course practicing a roll with a paddle float is a good way of gaining confidence for rolling without a float. It is also an excellent way to improve your hip flick until it is almost effortless. Use the float for practicing paddle braces until you can brace with confidence and can progress to bracing without a float with no fear of failure. Regularly using a paddle float increases your familiarity with it and helps you gauge its advantages and limitations for yourself. To improve your sense of balance, try reentering without the paddle float, going through all the moves on calm water. Then rehearse with your float in varying conditions until you know what you are capable of with a float rescue.