Not only does this mean that your Humans can deal damage to a defensive player by simply attacking another opponent, but if the chosen player is attacked, they effectively sustain twice as much damage
It's a very strong tool nonetheless and synergizes well with the previous hitting Perennial Behemoth which can be cast the turn before this and then play lands from your graveyard for Powerstones
Shivan Devastator Shivan Devastator is almost like a Blaze with wings
You get to play all the powerful white creatures Jace was previously excluding like Blade Splicer, while Sword of Feast and Famine is still good with blue cards when you pay the full sorcery price for it
Its still slow, but it works a lot like a Rampant Growth if you can get it into play on turn 1
Vintage Cube is more or less the fast mana format, and its easy to understand how one player having access to six mana to the other players four can lead to all kinds of snowballing advantages