Both. The splint allows the nerve time to be less irratated which can then relieve the pain.
Both. A wrist splint with the wrist in neutral (straight) will minimize the pressure in the carpal tunnel. Especially valuable at night when we tend to sleep with our wrists flexed.
Both. In many patients a wrist splint that holds the wrist in a straight position will help relieve symptoms. The goal of the splint is to keep the wrist straight, as bending it either way increasing the pressure on the nerve. Many patients may only need to wear the spiint at nighttime. Only when a splint no longers controls the symptoms would further treatment be necessary.