As far as Dredgevine itself, the most important piece of the deck is Vengevine, which much like Bloodghast is a creature that can return from the graveyard for free
On top of all of this, it is graded a PSA 10
Howling Mine effects are great enablers for this strategy
It was so hard to get ahead with Emeria Shepherd due to its prohibitive cost and otherwise underwhelming body, but this little mythic helps the Shepherd get ahead
It has the cheap and strong Mist Slash for just one Water and one Colorless Energy, doing an impressive 130 damage for just two Energy, but that damage isnt affected by Weakness, Resistance, or other effects, which prevents it from countering strong Fire-types, although at least it can get around Abilities or attacks that reduce or prevent damage
Absols cult following and the limited availability of Full Art and Secret Rare versions continue to support strong secondary-market prices