Putting ISK as an item makes it “offline” and anonymous and saves you one click if you would like to handout “welcome packages” to new corpmates or prepare “reward crates”.
“Production plans” are meant for complex production automation and saving clicks.
You could use it to prepare those “welcome packages” or “reward crates”.
…or “DIY kits”: https://forums.eveonline.com/t/diy-stc-station-container-x10-diy-assembly-kits