Look at it this way:
Fake an embedding, by Scaling an Object down along its Normals (to make room for the Margin) and then Scale it up again (adding the Margin).
Box, Spere, Cylinder return to the original, but Cone doesn’t and Triangle Mesh is not guaranteed (the Torus was a bad example, but most Meshes won’t ‘hold their shape’). Convex Hull is a bit of a mystery to me, because the Convex Hull of a Cone, for instance, is the same as the Cone.
