This note saves me some typing. I think it makes perfect sense. I think it is not quite appropriate to speak about L2 vs L3 link bundling.
Approaches can be different, both have their pros and cons, but both have a right to live.
So, I don't think this should be a driving factor. Link bundling, in the context it is presented in the document, seems to be MPLS-specific to me. It takes two to bundle links. For IP, this particular approach works very well.