For that very reason. They want to make sure you’re not claiming something to be defective just to then resell it later.
Sideshow will still make you do it depending on the product, but usually only for their own products. When I needed my R2D2 replacements, I had to destroy the ones I had completely. The first time they said it looked like I just unscrewed everything and could easily put it back together to resell, so I had to take it even further. When I needed replacement for my Man of Steel PF, I had to complete destroy the statue as well before they would send me a new one.
Sideshow actually used to tell you to get creative with how you destroyed stuff and you’d be entered into a prize contest. I remember one guy filmed his destruction of a GI Joe headsculpt I believe by inserting into one of the barrels of a double barrel shot gun and firing it off