Alright then, how is it not cheating? Making yourself invulnerable, with unlimited fatigue and magicka, seems pretty much the definition of cheating. It's giving yourself a serious advantage not normally available during regular play, using a debug console. I'm not arguing the morals of it, but I'd love to know how you think it's not cheating.
The same way that using mods which accomplish the same ends (basically making the player character invulnerable and unstoppable) isn't cheating. Whether or not they're widely used, such mods
are out there- so now we're faced with a decision:
A: Granting any edge to the player, in any way, is cheating.
B: Given the freely customizable nature of the game, which is a deliberate design decision, there's really no such thing as cheating- only "customizing play to suit a particular player."
C: Somehow invulnerability conferred by a "proper" mod, even if that mod does nothing but automatically activate TGM every time the game is started, isn't cheating while adding it on the fly via the console is.