Songs are powerful actions that characters can sing for free instead of paying ink, and Ursula Deceiver of All ensures that a single song delivers double the impact, completely overwhelming the opponent's defenses
Also, it works with any of your creatures, so it can be played outside artifact shells with any creatures that want to attack
The biggest common thread is that Gods are difficult to permanently get rid of
When you cast a Magic: The Gathering spell with Cascade, exile the top card of your deck until you find a spell that costs less than the previous spell, and cast it without paying its mana cost
This is just an incredible black enchantment, allowing you to pay up to 6 life a turn for some combination of mana generation, card draw, and board presence