So by your logic, all druids should stop buffing Thorns in PvP, and all paladins should never put up Retribution Aura. Okay then Worshaka
You're overvaluing both dispel mechanics and DA here. Silent Resolve provides 30% dispel resistance, and most of the time your buffs are either gonna be removed anyways, or your opponent won't have the time to purge everything (unless it's a 1v1 situation, which you yourself in your post just poo poo'd). BG isn't like 2v2, where having the dispel miss, wasting the other player's gcd/mana, and buying you extra time is worth something. In BG, dispelling is useful sometimes but using 3 points for a minor dispel protection is pretty much never worth it. DA bubbles, at 15% crit will give you a 1.2-1.3k absorb less than every 2 Penance
casts , and if you're healing in a environment such as Battlegrounds that little soap bubble isn't going to be worth anything at all, and is rather a complete waste of 3 points. It's a good talent for arenas sure, since it provides extra mitigation and longevity, but honestly even there games are almost never won because your DA absorbed a killing blow or something.
I'm not telling him to soloing everything in a BG, but the fact remains that most of the players won't be peeling you off. You can't tank the warrior beating on you forever. You can have your 1k bubble once in a blue moon and I'll take my 3k damage to the war, and we'll see who finishes the fight faster
Rather than tank the dude, kill him and hey look, I'm surviving cause the warrior's dead and I'm not taking damage.