Yes, but the representation as arcs allows one to defer the conversion to polylines/triangles until a later time.

As an example, if doing V carving, the appearance will be smoother if the geometry is imported so as to have arcs/curves, deferring the conversion to polylines/straight line movements until the last possible moment on the machine.

Arcs/Curves are also easier to work with if one needs to edit, and are more efficient in terms of representation/disk space/storage.