What is worst is that the joints don't bend in the same way as human body does. Try to pose looking at your body ends in a total fracass.
Most of the human joints have only two movements, bend and twist, no side-to-side, even so, it is able to do things that are impossible to be done by the meshes.
Our thumb has also only two movements, but these movements in the models are totally different, so it's almost impossible to make a figure pick something. With only a 90 degrees rotation of my thumb1 I pick a bottle, try to do this with Vicky or any other figure!!!!
There's no need for any deformer, the skin is not stretched or compressed with this movement, you only need to have the correct rotation axis and nothing more.
And making it worst, something must be wrong with the proportions of the body parts, we able able to bend, without any knowledge of yoga, that is imposible to be done by the figures, always the leg or some other part is too long to reach the correct destiny.

Stupidity also evolves!