This flexibility of being a two for one removal spell and win condition, or just getting in hard and fast with haste is excellent
When Cavendish is played, you can set 2 of your Don as Active, which can be used for a heavier Leader attack or to develop Koushirou
When you cast Apex Devastator, youll treat each cascade trigger separately, with each one searching for a nonland card that costs less than ten mana
Purification could see situational play in a side deck against specific matchups where Continuous Spell Cards are prevalent, but it may not be a staple card in most main decks due to its narrow focus
One is not necessarily better than the others, so any that fits your favorite play style is a good option
If your opponent tries to defend their life points by using defense position monsters, Red Dragon Archfiend can shut them all down by attacking just one