By reducing the casting time, this talent greatly increases the healing done per second when chain-casting Healing Wave. The potential healing per second is increased by 20% when fully talented, making Healing Wave the most potent single target heal available to a Restoration shaman.
The faster casting time also makes the spell less unwieldy to use in general and easier to land on a target that is about to die, since the heal will land faster. The talent is included in virtually every Restoration build.