I usually only talk about IA because that’s the program I use and know for storing items. Haven’t tested this feature of GDStash since IA allows you to store items without leaving the game.
I honestly don’t know because I haven’t researched this issue much but for now I think it’s some bullshit/technical negligence and trust the author until proven wrong by more knowledgeable person. Here are some discussions if you’d like to have a loot yourself
also the source code is here
It’s certainly for responsible and mature players that know how they want to experience the game and don’t feel regrets because they didn’t foresee GDStash could lessen their enjoyment of farming items.