Poison runs are valid if you can get your hands on some insta-poisons like Bouncing Flask & Deadly Poison. Combine that with a Catalyst & finish it off with a corpse explosion, you can kill the bosses in 3 turns with good draws. Upgrading Catalyst & Corpse Explosion is a must in this though. For relics deffo Snecko Skull, one that gives bonus mana & maybe a Specimen in case you cannot finish an enemy & they have a lot of minions. In that case, you could focus your poison on minions to kill them off faster. Wouldn't recommend Noxious Fumes as card since it stacks too slow in my opinion.

Imo it's part of the game & it can make or ruin a run. So I wouldn't see why it should be banned.