Bringing back a 1-drop is an easy enough feat, though Grist will still flip to its planeswalker side if you already control it and bring back something else instead
Many of these creatures have flying, unblockable, etc
In a world where cards entering the battlefield matters more though, flicker or blink effects, which make a card leave the battlefield momentarily only for it to enter the battlefield again, become much better
With it not effecting the board and the ability to scry for various amounts make it easy to tag on to things in a balanced manner and not make them too powerful
As the deck slowly evolved, Primal Amulet has become a utility piece that does not always want to be flipped
Then, we knew we had to make it even more exciting so we could stuff it with fancy foils and rares and/or mythic rares