The problem with using morphs  to actually pose a figure is that a vertex travels from the position it has at "morph set to 1" and "morph set to 0" in a straight line.

So an arm looks good at "1" and at "0", but not at "0.2" or "0.75".

You actually could inject "pose morphs" for static renders, and Poser would have no problem to handle that as it would be just another FBM , but it won't work for animation.