I don't have to go into too much detail to explain why this card is one of the best defensive options out there, despite the fact that it's in spirit. For starters, it's a 0-cost attachment. It's only main downside being that it requires a fair bit of resources (I'd say at least 3) to really begin to shine. Thankfully there are many cards that can help booster this from Errand-rider to Steward of Gondor the latter of which provides any character the necessary trait to be given this attachment. Though it's easy to just throw this on Beregond or Aragorn and call it a day, thanks to the Steward's granting of the Gondor trait unlikely Heroes like Frodo Baggins or Erkenbrand can take their defensive qualities to the next level.
I have seen moderate success in secrecy decks, throwing a Resourceful on the Hero I intend to attach with Blood of Númenor (in most cases this is Eleanor). It's a great card and one that I see myself consistently using despite where the card pool may go.