The aggro decks typically beat you by miles, not by inches, so having the giant blocker means more than gaining a few life
Elesh Norn is especially brutal when headlining Stax, Tokens, and Hatebear decks, where she essentially turns all your annoying mana-efficient Creatures into real threats while making your opponents' small utility Creatures disappear on sight
Early game you can get extra XP and resources from completing bot matches, but you only get limited XP through PvP
Something about a creature that just Lightning Helixes your opponents turn after turn feels right
But at least so far, none of the Secret Lair drops can really be considered a bad deal from a financial perspective (and this is without considering the possibility of getting a valuable bonus card)
Yes, it enters tapped, but whenever you use its mana to cast a creature, youll get to scry, which makes a huge difference in the long run