Currently, I have problem to figure out what the use case of a stack inserter.

Firstly it cannot be used to grab items from a mixed belt, since it might got stuck.
https://forums.factorio.com/download/file.php?id=87769

Secondly, it cannot be used as the output when quality modules are inserted ...

Maybe you should provide more informations.

For me, with Arch linux, KDE wayland ( with no sddm), for details, installed with

pacman -S efibootmgr grub intel-ucode\
plasma-wayland-session plasma-desktop plasma-nm plasma-pa pipewire-pulse dolphin kate konsole firefox rustup libreoffice-fresh-zh ...

For a normal inserter, they move all the items into machines, but for stack-inserter, things become different.

When the belt has 2 different items (with limit 4+16 = 19 for example). And thus the machine accept at most 4+max_stack items.

For stack-inserters, it will grab exact 16 items, but in ...

(To test whether people with poor English can submit game runtime errors, the entire article was translated using AI, some game terminology may be inaccurate, please understand.)

(Screen captures are only availabled in https://jump2.bdimg.com/p/9243507661 since images in tieba.baidu.com cannot be ...