It’s important to protect your hands with rappelling gloves during rappelling or rescue situations. They also prevent your hands from sliding and allow a firm, secure grip.
There may be debris embedded in your rope or you make come across rough surfaces while you are manipulating your devices and equipment. Gloves will protect your hands from cuts and abrasions by creating a barrier on your hands. They will also protect your hands from possible heat created by your high angle system when the rope can get quite hot. Gloves also help you form a secure, strong grip when your hands can be quite slippery in certain weather conditions.
Light-weight gloves don’t help with protection from the heat production much but they do help protect your hands from injury. There are some light-weight gloves with leather on the hand grip and a breathable back that are considered sport gloves but some complain that their palms can sweat a lot from the leather patches on the palms. There are some medium weight gloves that are specifically designed for high angle systems. These are nice gloves to have that are equipped with a complete leather palm and a nice breathable back and usually a velcro strap to keep the gloves in place. Some heavy weight gloves are actually made with an extra layer of leather, but this can actually get in the way at times and can be quite cumbersome. Fingerless gloves allow you to use your tactile senses, but this exposes your fingers and expose them to possible injury.