Don't answer terrible lazy posters. Report them instead of creating more cleanup for me.
It's not 5 points in my mind considering that the 3 points for Archangel are taken from Inner Sanctum. While being undeniably a good talent it doesn't have much to do with efficiency.
The remaining 2 points for Atonement are a larger investment since they're taken from either Veiled Shadows/Darkness/Inspiration.
Taking Atonement doesn't lock you into a completely different healing style, you can still GH/ToT spam just as you would with your build but you have the option of adding in Smite whenever it makes sense. There are plenty of situations where it can be quite good.