openGL vs openframeworks : GPU vs CPU

Hi dear colleges,

I’ve been diving into computer graphics, openframework and openGL for some weeks now.
I now know that graphics ought to be computed as much as possible in the GPU.

So, material, lights, translations etc should they all be programmed using shaders?
I mean, all the functions in openframeworks like , ofRotate, ofTranslate , they are computed in the CPU?
Or when I put them all in a ofVbo, are they then computed in the GPU?

I just wonder , for the best results, do I have to program in GSLS or do I use the openframework classes.
When do I really need to use fragment and vertex shaders?

My goal is to make animated 3d scenes

Thank You