"Affects all other auras" Be nice to do a test to see if it affects only paladin auras, or any spell classified as an aura (viz: Tree of Life, Trueshot, Leader of the Pack, etc.).
Without testing it, it would seem that it would have to affect all, because if it only affects pally auras, it would seem pointless that you have to have @ least 1 other pally in the group to make this truly worth it. The immunity is nice, but if it requires the pally to have Devotion aura up, then it would seem pointless if it "affects all other [paladin] auras." UNLESS the interrupt affects all members under the influence of DA at the time of casting, and would allow you to cast it, then quickly switch auras, with losing a second from the overall duration .
This is all general guessing; but it would be nice if it did. Spec a point into it tonight and give it a shot, post the results if nobody beats me too it.