This is made a lot easier with cards like Treasonous Ogre and Magnetic Theft
Siege Rhino (2014), Dragonlord Ojutai (2015), and Thalia, Heretic Cathar (2016)
(See rule 601, Casting Spells.) Such costs are paid at the same time as the spells other costs
Like Tormods Crypt and its ilk, its a one-shot effect that a Dredge player needs to tip-toe around, but doing so is often impossible
Protection from red isnt nothing either being able to ignore board wipes like Blasphemous Act and Structural Assault is extremely handy, and the ability to hold off a bigger red creature later in the game like Etali, Primal Storm or Inferno Titan can save you from a lot of unwanted damage in certain matchups
Tribute Mage Like Trophy Mage, Tribute Mage benefits from finding cards you can always cast since you had the mana for this one