The other significant reason is that post-board games tend to go longer and you often do not know what cards youre digging for until the game has developed a bit e.g
It has flash, so its a perfect response to that Demonic Tutor or Eldritch Evolution, allowing you to steal whatever you need and ruin your opponents plans
She rarely needs her emblem to matter
(It can't be blocked except by artifact creatures and/or black creatures.) Enchantment - Aura Color tag templates(None) Dirge of Dread All creatures gain fear until end of turn
It coming down as an instant is also pretty huge, as already described by ElshaElsha getting blocked "for lethal" and then you pumping her bigger to have her both live and trample over the top for Monks and damage
Each of these snazzy pieces of jewelry functions similarly to Lands, adding one mana of a single color to your pool at no cost - but while you can only play one Land per turn, you can slap down as many Moxes as you like