It fits well into Abzan beatdown plans that want to apply early pressure while padding life totals, especially alongside blink effects like Ephemerate or recursion engines that reuse enters triggers for steady advantage
I got a Library of Alexandria down in early in the game, but Tuukka was able to kill off my Enchantress with a Fireball
If you find Borborygmos with a Griselbrand you will have so many lands free to machine gun everything to death
If you cast it without a Time Vault, you could go find it and threaten to take infinite turns, next turn
However, Aragorn's strength lies in tying your deck together
As a hypothetical curve to show quite how obscene this can look, you could cast your copy of The Ringhart Crest on Turn 2, on Turn 3 you use it to resolve Questing Beast, and then you get to land your Yorion on Turn 4, blinking the Crest to turn it into a Kolvori