I have two clients (a husband and wife) who swear by them, and wouldn’t work out without them 🙂 Of course, when we work on exercises requiring manual dexterity, they have to take them off (so in those cases I guess you can call them a hindrance). So, the long and short of it is that they can be either a help or hindrance; it will depend on what you’re doing at the time, AND perhaps more importantly whether the person using them sees them as a help or hindrance (after all, “perception can be reality”).
I hope that this helps.
Personal I love gloves. Not only do they help prevent you from getting calluses, but gloves with wrist wraps help provide stability to the wrist. This is especially great for me as I have fractured both my left and right wrist playing football. I do have clients and colleagues who prefer not to wear gloves, but some who do. As LaRue said, “they can be either a help or hindrance”. The type of glove will also matter as they have some for general fitness which are less bulky and provide basic covering or you can get into the weightlifting type of glove which can come with wrist wraps and more cushioning in the palm area. Some popular brands are Harbinger, Altus, Schiek, and Valeo. Depending on the use there are alternatives such as chalk, lifting straps, and exercise grips (covers palm only).
I have a couple of pairs, but am not married to using them. I do recommend sometimes for certain female clients, based mostly on the workouts we go through. I see some guys come in with gloves with straps, hand clothes (yeah) and paper towels. To each his/her own on that one, as long as you can handle the load or it protects your hands.