You lock yourself into only one color and sometimes green is powerful enough to justify it
If the legendary nonland card exiled this way is a modal double-faced card, and the back face is also a nonland card face, you may cast either face, even if the back face isn't legendary
It costs less across the board and its dash cost enables a more diverse land base
Cutting the $30 (currently) Ojer Taq, Deepest Foundation and the $45 Anointed Procession really slows down your Gnome production, but they can be replaced with some general artifact creature generators like Thopter Spy Network and Thopter Foundry
Being able to deal with Tarmogoyf for one mana (the previous best answer was Liliana of the Veils second ability or a Ulcerate) was a revolution for the modern format
Its nice that this card is strong in 1v1 as a damage dealer, and in EDH, the discard and draw effect scales according to the number of players to compensate for the fact that a 5/5 with flying and haste is just alright in the format
