Trying not to mention what has already been said but:
Gloves that wick well will also help to keep you cooler (and cut offs are not a significant disadvantage in this sense, due to surface area to volume ratios and blood flow.)
The main reasons for choosing cut off gloves as opposed to more protective full finger gloves (given that both can keep you more or less equally cool if made out of the right materials) is partially personal preference, but often relates to better feel when dealing with zips, packed food/energy, gear adjustment and not having to take them off when working on the bike, some also claim a superior feel for the brakes.
What other activities are they useful for: potentially anything where you grip anything but don't need your finger tips covered or are willing to take the risk of finger tip injury, also for typing in the cold. I use gym gloves for cycling, better value, fit AND durability (in my case) than cycling equivalents at twice the price. I only use actual cycling gloves when it comes to full-finger + extra protection, or waterproof + breathable (since those are expensive in any sport, so I may as well have something with more attention to cycling relevant details).