Umm, what ?

A cube has eight vertices.

If I subdivide it, it has 28, but only the original 8 can be manipulated in Poser, as the 20 new ones are just "virtual".

If I "freeze" the subdivision I get a high res cube with 28 "real" vertices.

Morphing the SubD cube limits me to moving those 8 vertices around, as the others will be re-generated constantly.

With the high res cube I can move all 28 vertices completely independently from each other.

So of course I can have much more morphs with the high res cube.