For Commanders that can afford it through cost reduction like Rowan, Scion of War, or Treasure generation like Prosper, Tome-Bound Crackle with power can end games in an instant
White isn't particularly known for its ramping ability
The downside is that since you have to attack with Varragoth, you have very little agency over what it trades for, but that seems like a fair trade-off for a free Vampiric Tutor
In Historic, at least for the time being, all we'll have is Predatory Sliver, which just isn't enough
As the total damage threshold for commander damage is 21, its a lot easier, in many ways, to strap up one creature with buffs and evasive keywords in order to deal 21 over one or more turns than to deal 40 with a wider board
Very cool