after effect have a function call “mesh warp” ,it just like applying a texture onto a mesh,then you can deform it base on the “mesh vertex”. this function sometime useful than Bone deform.for example , simulate a flag animation, a bouncing belly.
You can simulate that with skeleton deformation.
This is a fast example:
flag.sfg (104 KB)
It takes a bit of work (and depend of what animation you are making… but it works).