"Holes in metal or another hard material will often have sharp edges.
[5] Electrical wires,
cord,
rope, lacings, or other soft vulnerable material passing through the hole can become
abraded or cut, or electrical insulation may break due to repeated flexing at the exit point of the casing of a junction box for example.
[5] Rubber, plastic or plastic coated metal grommets are used to avoid this. Tight fitting rubber grommets can also prevent the entry of dirt, air, water, etc.
[5] The smooth and sometimes soft inner surface of the grommet shields the wire from damage.
[5]
Grommets are generally used whenever wires pass through punched or drilled
sheet metal or plastic casings for this reason.
[5] Molded and continuous strip grommets, also known as edge grommets, are manufactured in a wide variety of sizes and lengths expressly for this purpose; they are usually a single piece which can be inserted by hand. "
Yeah, I'm making this shit up. Sure... It's all part of my plan to be mean to some rando on the internet.