I see. So is the question really is whether there is some middle space between 'magic' and 'normal as in the real world?' I'd say there is, for example most people wouldn't probably see giant creatures as magic, even though they couldn't really function under the real world physics. I think in a similar vein it might be easier for people to accept if fighters and such did amazing physical feats* instead of actually shooting lightning bolts etc.Well, for an example of where it becomes important: Are Fighters "magic"?
They don't cast spells. But they're certainly able to take punishment they should not be able to do so if they lived by Earth physics, at least in every edition of D&D I know of. They can pull off some actions or feats that border on physically impossible, and all it takes is some training to be world-class best at at least one or two tricks.
But if you call Fighters "magic" quite a few folks have a conniption fit. Fighters getting anything that even looks vaguely like "magic" is often anathema. Many folks--even those who see "supernatural" as encompassing a much broader space than just "magic"--get super wary about allowing any recognition of certain classes as doing anything beyond the limits of mundanity.
Personally I feel the fighter's mundanity should be tied to the level. 1-5 is 'realistic' 6-10 is 'Hollywood mundane' and beyond ten we can simply accept that they're epic legendary fantasy heroes and can do blatantly non-mundane stuff.
Though I'm not sure that any of this is super closely connected to definition of magic.
(* Probably more like Captain America in scope, rather than Thor.**)
(** Who can also shoot lighting bolts, but that wasn't my point.)