We exist as matter, and taking a practical viewpoint rather than a philosophic, quantum mechanical, or relativistic point of view is best. You can successfully and pointlessly argue that since matter and energy are the same thing, we are energy - yeah, true, but not on the level we as biological entities operate. So, how does that knowledge of deep duality (matter=energy) help Biology? Not all that much.
Just consider that Biology has very successfully operated as a Science without Quantum Theory or Relativity since the the very earliest Naturalists and Herbalists. Biology depends heavily on classical physics, chemistry, but not all that much on what happens inside black holes.