Oh I definitely agree. I feel grading is only good for museum type pieces (say like a one of a kind item or a console), as like you mentioned, you can find a good condition copy of the game ungraded for a fair price.

I never understood the obsession with grading stuff, especially something as common and lacklustre as a fortnite physical copy. I'm the same with sealed games as well which I just couldn't imagine paying double for some plastic. Each to their own I guess, their money not mine :)

I think the grading was just a racket made to bolster collector prices, so people could get significantly more than what it's worth. It's not without it's merits for very rare items, even in the collectors scene. It can give confidence that you are at least getting a certain level of quality based on whatever criteria they use. But I find it mostly arbitrary, and what I'd consider very good or mint, isn't what they'd consider very good or mint, and I know people with rated items, and I've seen pieces which I wouldn't consider mint(above 90%) as more than very good, or even good. I've also know of at least one instance where one guy got something rated as good, and we both considered it mint, because it really was flawless.