Levers are usually tapered so as to be able to penetrate into the base of the intended work piece, thereby finding it easy to lift it up.

So the centre of gravity moves toward the end of the lever for ease of actuation.

In lever, The bending moment is maximum at the fulcrum and minimum at the ends, therefore the levers are tapered from fulcrum towards the ends to save the material at the ends.

The "tapered levers" shown are all handlees which points to the reason for the taper. They are tapered to fit the hand of the user.

The taper has no bearing on the function of the leaver. There may be a taper for esthetic reasons, but it is not functional.

DrD