This can affect basic Plains, or even affect a dual land with the Plains type such as Temple Garden or Godless Shrine
It's effect is on-going, and you can build around it with artifact creatures or things you can't target (like Protection from Black) or indestructible stuff that can't be destroyed at all
Commanders like Feldon of the Third Path can make good use of it, for example, or it can pay for the vast majority of Herigast, Erupting Nullkites emerge cost
If, like me, you consider this more of a Wrath effect then it looks insane
If you already have a board advantage and destroy all the lands in play, your opponents have fewer resources to kill your creatures or wrath the board, so youll maintain your advantage
It'll come out more quickly in an artifact deck and also helps you gain access to more cards each turn