Scientists attempting to answer this question studied over 5,000 snowboarders. Half the snowboarders wore wrist braces; the other half didn't.
Those wearing braces had significantly fewer wrist injuries. Only eight wearing the braces ended up with a wrist injury, including three fractures and five sprains. Strikingly, 29 injuries were recorded in those who didn't wear wrist braces. Two of these injuries involved fractures, and 27 were sprains.
The results of their study led the authors to recommend that all snowboarders wear wrist braces to reduce the chances of a wrist injury.