It's game logic.
Fallout 4, you can get woods out of a singe wooden board, or you can get 1 metal from a nail, but you can only get 1 metal from a very big machine (my memory of the game is rusty, don't bite me, but you get the gist of it)
Dying light, night goes from 9pm to 6am but only last for 5 minutes.
You're not supposed to question it, just go with it, since most of the time it stop bothering you after a while:
-Fallout: you get more scraps than you ever care for, in the end you get 1 metal scrap from a nail that weight less than 0.1 kg or 10 metals from it does not matter at all, woa a big pile of rusted metal that weight 20 kg get you 1 metal scrap, still does not matter, something else will conpensate for it.
-Dying light: the night is there to scare you, having a long night system while player can just sleep it away in 3 seconds is just stupid, so they opted for short af night, but it's intense.
The trading system is there to "simulate" the situation, don't read iton it too much unless you want to mod a realer economy system in.