Ever tried to insert a micro sim card into a spring-secured slot (like in the Lenovo X1Carbon)?
It is tedious because your fingers are too fat! (Yes even tiny fingers are too fat ;)
No imagine you have to install 400 of them in a short time. I am pretty sure the poor mortal who has to do the job will probably go bonkers ;)
This small thing at least makes this job easier.
This one has very thin latches (0.1 mm) so print with fine resolution.
You want to lay that thing flat before printing as well ;)