The screws we provide with our enclosures are M2.5 10mm screws. They are designed to screw directly into the base plate of the enclosure, and don't stick out too much on the other side.
But sometimes, you just need longer screws. For example, you can affix your enclosure onto the Raspberry Pi 7-inch Touch Display. It has the same mount holes as the Raspberry Pi, and has standoffs to mount into. You can use the longer screws to affix the base plate with the Raspberry Pi mounted on it, to the Touch Display, for example.
This set of 4 screws is useful in that scenario, but just as useful in any other where you need 12mm M2.5 screws! 😊