So you know you are only going to have them for a very limited time
For example, if you cast Junkblade Bruiser (a creature with a mana value of 5 and an ability that triggers whenever you expend 4) by paying its full cost of five mana, you'll already have spent four mana on spells before Junkblade Bruiser enters, and therefore its ability that triggers whenever you expend 4 won't be able to trigger at all that turn
While it doesnt give you the buff and haste that you can get from Finale of Devastation, this card will still make it into lists that have specific tutor targets that win games
Demonic Tutor is also restricted since this black sorcery can easily tutor combo pieces, which there are many of in this format
An example is Prophetic Bolt, which combines the effects of the red card Lightning Blast with those of the blue card Impulse
A third Drivnod causes abilities to trigger four times, a fourth causes abilities to trigger five times, and so on