Note that this is somewhat of a duplicate feature since its already possible with displacement modifier + a Blend (Gradient) texture.
See Post #2 here: https://devtalk.blender.org/t/idea-add-shear-option-in-simpledeform-modifier/16312/2

Some users dont find it obvious to use displacement for shearing though.
And I agree that intuitively you would look for this kind of thing in the SimpleDeform modifier first.

Pros:

• Less clicks to set up.
• No texture needed (tiny bit less memory).
• No fiddling around with texture clamping. (see ears in displacement example, attached picture).

Contra:

• More Clutter on SimpleDeform UI