on top of that to brake the linear deformation of blend shape,
Blendshapes dont need to be linear, most users asume they have to but they dont. You can make blendshapes do curved arcs, or any interpolation really. I use blendshape nodes as general point calculation machines because they allow me to solve
aA+bA....+qQ
like mathematical equations where capital letters are matrices containing point vectors and small are scalars. Since most interpolation types are those kinds of weighted equations its reather easy to interpolate in any way one wishes.