Is there any point in leveling Tempter's Gravel to tier 2 or 3? The description for the invincibility for tier 1 and 2 are the same but tier 3 says it gives Exalted in a radius instead of a protective wall. Does that mean for tier 1 and 2, the effect only lasts while you're close to the Sanctum Stone while tier 3, you can move away after getting the buff?
Also, does the tier 2 deal any significant damage?