Temporal Ripples is the actual healing effect that is triggered after receiving damage.
The major advantage of this talent compared to its competitor Ice Barrier (IB) is that it can counteract more damage. However, this is fairly difficult to achieve for two reasons:
The time window in which damage is “absorbed” is limited to four seconds, which means that Temporal Shield can only be used to its full extent if the incoming damage is highly bursty. For example, it can work well if you see an enemy casting a hard-hitting spell (such as Chaos Bolt in PvP) that would exceed IB's absorption. For any situation where damage is less spiky, Temporal Shield will most likely be inferior to Ice Barrier.
The fact that the shield does not actually absorb the damage but rather reverts it over time makes it troublesome to use at low health. The reason is that even though eventually all lost health is restored, you may die before the healing can take (full) effect.
Another benefit is its being off the global cooldown, meaning it can be triggered basically at any time.
Ice Barrier, on the other hand, is a lot more forgiving, since its timing is not nearly as critical. Furthermore, it works against prolonged damage, can absorb a lot of damage independent of timing, is not affected by healing-reduction debuffs, and can be “stacked” if it cools off while the buff is still active (basically allowing you to benefit twice from it when the next enemy arrives).