heck, you technically can even run Horus the Black Flame Dragon LV8 and Horus the Black Flame Dragon LV6 in your side deck, to side in against a Spell-heavy strategy, because LV6 will always be able to destroy a Ken or Gen you summon to the opponents field in battle
It answers a lot of problems when a player is casting things for free, which can get out of hand quickly
If you cast a spell "without paying its mana cost," you can't choose to cast it for any alternative costs
Shiranui Spectralsword of Sunset [Tuner ATK 800/DEF 0] You can Tribute this card, then target 2 of your banished Zombie monsters, including a Shiranui monster, except Shiranui Spectralsword of Sunset
And because we worked so hard to get him, Swiftfoot BootsSwiftfoot Boots is jumping in to protect Sauron
Now you just have to open some sweet rares.