One nice thing about fingerless gloves is that they can fit snugly into the space between your index finger and thumb while holding the handlebars.

That's the problem with full-fingered gloves -- IF the finger length is too short. When you jam a handlebar in your hand and the glove's fingers are a little shorter than yours, the fabric pulls at your thumb & forefinger, causing discomfort.

Personally, I ride with full-finger gloves because my hands can get sweaty enough that the brakes & shifters get slick. I just have to shop around a bit more to find gloves that are long enough.