I know a lot of healers are very pro stacking +heal, and if you know much about me you know that I am not. Of course I want +heal, but my main priority is my mana.
So, yes I use the Darkmoon Card: Blue Dragon, which you can obtain by turning in the Darkmoon Beast Deck. I can tell you that I personally used this card all the way into WotLK, up until they changed it to no longer scale perfectly.
At the moment knowing my card has procced doesn’t really change my game play that much. But there were times in the past that I had, say, an on-use spirit trinket… that I would want to activate if my blue dragon buff was on. Also, if it’s not an emergency, I don’t want to blow innervate while the buff is active and waste it.
For those reasons I love this weak aura. I didn’t write it but I use it and would recommend it 100%