Because they're from the Metaverse. So they have some of the quality of that place. That's why stuff that makes no sense to make what they do still work. If I used real-world versions of the same junk it'd just be that- a pile of junk. I can replace some of it with real-world items as long as they are pretty much identical, but that's because of my cognition of them being the same. But that takes some practice to pull off. Knowing they are from another world makes it easier to get into the right mindset.

...it's kinda circular non-logic, honestly.