Im definitely always in favor of cards that can punish the prevalence of green ramp and this one offers a tangible reward in the form of your own temporary mana acceleration
The trick here is to find an efficient way to get your life total to zero -- could be Selenia, Wall of Blood, Ad Nauseam, whatever -- to immediately flip the Angel, then use either Tainted Sigil or Children of Korlis to regain all that lost life and voila, you now have a supercharged Serra Avatar with flying ready to 1-shot opponents
It has a tapped ability that gives out three mana of any one color
Plus, every time your dragons deal damage, you get to dig through your deck and even bounce dragons back to your hand to dodge removal or retrigger enter-the-battlefield effects
There are a lot of options for doing thisyou can even print out your own tokens with custom art
Then exile it.) Cultivate Cultivate is a three-cost (two generic and one green) sorcery