When equipment becomes unattached from a creature, so do its effects
Raven Eagle Raven Eagle fits beautifully into Standard decks that care about incremental advantage
I imagine something like Entomb to tutor up a Bolas's Citadel, then casting Mox Amber to reanimate the Citadel and popping off from there could be a good start at what Moira can do, but I'm sure people can come up with far scarier lines than my quick example
2 Nicol Bolas, Dragon-God Dragon-God comes in as the lowest costing Nicol Bolas planeswalker, only costing one blue, three black, and one red
Its a great little value engine that draws at least one card a turn cycle and potentially far more if you build with tons of instants
Ultimately, the choice is yoursbut if youre on the fence, you should go for it