For many collectors, the argument is simple, a promise is a promise
Just like Joshua, you can transform her at will for 6 mana (the magic number in this set), and for the trouble, you get a 6/6 flier that makes a couple copies of your existing enchantments before giving you the exact mana needed to cast Progenitus
Enchantment creatures that became enchantments Another trope we explored was the idea of creatures that, although dead, still have a presence
Its a resolves trigger rather than a sacrifice trigger, so you could, in theory, put the lore counter onto your saga to trigger its final chapter, then remove a counter before you have to sacrifice it
This is an incredibly useful card to use early when there aren't many cards in the player's graveyard, so they can increase the chances they get what they want