Not when your co-healer is a strong asshole :P who knows that you have Bene off-CD
I do agree on the fact that a CRIT EssenDigni can do a similar job as Benediction, and if the tank got Convalescence because the spell got a potency enhancer...
But show me a case where Lustrate can heal for almost 20k in a single hit...
Beside, with the 3.0 change of lustrate, Benediction stay as the only healing spell bypassing the ClericStance
And that is an enormous advantage XD