Even when he was sealed he was capable of appearing in either a ghostly reaper-like form (such as when he appeared to Alito's, Girag's, Vector's, Dumon's and Marin's past lives) or in a shaman form (such as when he appeared to Mizar's past life) on Earth and in these forms he was capable of brainwashing humans as he did to Alito's friend, the prince, his advisers and Girag's comrades as well as Mizar's neighbors and allegedly used this form to cause the tragic deaths of all the Seven Emperors and embed their souls with the "Over-Hundred Numbers"
Or why were throwing in Wizards that care about big spells when Elves are generally cheap
Following any of these cards on turn three, Deceit is an easy turn-four play that bounces and discards something
ramping is added to the players hand
To be fair, the impact of the Probe is not that huge in Commander than in, lets say, Vintage
The deck generally tries to make that even fewer