Along with Duelists Convocation International, the governing body that sanctions tournament gameplay, Wizards of the Coast began announcing banned cards that cannot be used during official tournament play
While this does include your own characters, being able to immediately shut down any buffs that rely on cards being undamaged can go a long way
This Orzhov deck doesnt have any crazy shenanigans or combos going on, opting instead to grind its opponent down with discard spells and solid creatures
Its far easier for your opponents to kill your 1/1 Elvish Mystic than destroy the basic Forest that your Rampant Growth fetched
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For example, running a commander like Niv-Mizzet, Parun highly encourages the use of multiple cheap card draw effects to ping as many targets as possibleand, of course, win games out of nowhere when paired with Curiosity