I like gloves because I like my hands, and I particularly like my hands with the skin on – not ripped off by some leadrope or lunge rein. Also I hate the cold and I live in the U.K. so I have expensive gloves and I use them. However this evening I started to think about their effect on my riding, when little stallion had a few rather unkind things to say about my hands and then I realised I had forgotten to put them on.
Why do gloves improve your riding?
(Good) gloves increase the friction between your hand and the reins. That means that you can keep a more relaxed hand and still have the reins secure. In turn this relaxed hand means a more relaxed forearm, as like horses we keep the muscles further up the limb, away from the digits. If your forearm is relaxed you have softer more responsive hands and your stallion stops whinging (or whining and complaining in American). Everyone’s a winner. My gelding also tells tales on me, but apparently I wore gloves to ride him.
I have ambitions, Sox merely likes grass and doesn't see why he has to put up with fools.
Equine Biomechanics 
Never thought much about it, but I do wear gloves all the time when I ride to protect my fingers from blisters/rubs. Now I realize an added benefit. Interesting.