An uncounterable 15/15 with flying, protection from colored spells, and annihilator 6, upon entering the battlefield, Emrakul's controller takes an extra turn after this one
You wont be as incentivized to play the remaining enchantment removal like Seal Away and Ixalans Binding with Cleansing Nova in your deck, but theres no harm in having the versatility to destroy all artifacts and enchantments as well if thats necessary
Even in Commander, the need to tap down 12 power of creatures for something like Evendo, Waking Haven is utterly brutal
Based on the latest market prices tracked on TCG Stacked, Gloom is worth about $0.08 USD
Since they can always bounce themselves, they give you a starting place for repeated (1) ETBs, and (2) creature casts
Granted, thats a game with 4 players giving you 6 tokens