In a format like Commander that relies on specific cards, you can easily get it to your hand for use if that card is legendary
You have to have that additional land in your hand
Earthcraft has long been banned out of basically everything, including Legacy, thanks to interactions like: Turn 1: Wild Growth Turn 2: Earthcraft, then drop Shrieking Drake and respond to its trigger by tapping it to untap the land with Wild Growth on it
Whether you have a powered up Nykthos, Shrine to Nyx or a twice-enchanted Forest to untap, Treachery lets you grab the best creature at the table, often with a positive mana advantage
Jonah Jameson Saffgor: This is a flavor win from several angles, but it helps that JJ here can also play with the big boys alongside a card like Aggravated Assault, because boy those Treasures sure do enter untapped
In Modern, instead of the iconic Hymn to Tourach, we get Wrench Mind