Collectors highly seek after it for its rarity and power
It's a variant on the level up mechanic that uses triggered abilities instead of mana payment to level up
Swords to Plowshares is premier removal in Commander, Legacy, and Vintage, while Modern has to make do with Path to Exile
Other prominent mechanics that incorporate (or freely enable) sacrifice include: Food, Clues, Treasures, Sagas, Unearth, Encore, Evoke, any other temporary tokens such as Faerie Artisans or Hostility, cards with Upkeep, Quests, Exploit, Casualty and now Bargain
Whilst you're doing these solo gates, you'll also unlock more structure decks, cards, and gems for purchasing card packs, the last of which you'll need later
Though they have a glaring weakness in that destroying their field spell Toon World destroys them as well, theyre all capable of attacking directly unless the opponent controls a Toon Monster