The Merfolk will quite literally stream out of your deck once you assemble this value engine
Fast aggro can run under her , and counters still matter
That Special Summoned monster's ATK becomes doubled, also it cannot be destroyed by battle, except by battle with a "Number" monster, nor by card effects
Some pre-release lists ran two, but you generally value more Extra Deck space over the capacity to summon this a second time (especially since Loading
They have a ton of monsters which can negate attacks, a monster that flips everything face down, and field spells that allow direct attacks when everything on either side is face down
You can make this deck even more consistent by adding a second infinite combo involving your alternate commander: Yuna, Grand Summoner