Thematically, youre building up the story of another character, taking a lowly Llanowar Elf up to a massive 10/10 creature, and now you can tell their exploits throughout time (or at least until you win the battle)
These armored soldiers protect The Golden Throne and the Emperor himself
You could technically run it without explicit artifact support, but you'll need to get the brunt of your energy from other sources to make use of her abilities
Shes a payoff and an enabler for graveyard shenanigans, which makes her incredibly valuable
Blue suprisingly has a number of good options for supplementing aggro decks without sacrificing the control archetype, such as Stasis for an additional Winter Orb effect, Snapcaster Mage, Vendilion Clique, and Man-o-War for tempo/efficient beaters, and multicolor support in the form of cards like Geist of Saint Traft and Psychatog