Finally, a single card that makes hero treebeard really good. Attack for 7 and quest for 6 in a single action. It can be hard to find a spirit resource when playing an Ent deck, however.
This card transforms the game. "Is this game solo-able with a single hand?" is a question you often see asked about LCGs. It seems that people want a streamlined, solo CCG-style card game experience that doesn't require playing as multiple players, doesn't require 2 hours per session, and doesn't have an unappealing theme. With Bond of Friendship, you can now more easily take on scenarios with a single deck, finish up in less than an hour, and best of all, it is the Lord of the Rings LCG.
This was one of those cards that I never thought I'd actually put into a deck, but I've found that it can be quite strong in conjunction with a Woodman/location attachment deck in a multiplayer game. Specifically, in quests that spit out multiple locations over and over (i.e. Lost in Mirkwood) it may not be feasible to travel to and clear all those locations before you need to make progress on the main quest (and this is only exacerbated in quests that include objective-locations that are immune to player card effects). As the game goes on, the staging area fills up, making it increasingly difficult to quest over when you need that big push at the end. However, if you have spent the game spreading out location attachments (Explorer's Almanac, Guarded Ceaselessly, Guarded cards, Thrór's Key, Power in the Earth, etc.), you can effectively neutralize an entire staging area's worth of locations for 1 resource (I've negated up to 10 in a two-handed game before).
Is it niche? Absolutely! Is it lots of fun to pull off? Absolutely!
Personally I choose to house rule that the useless Archer trait on this guy and Silverlode Archer is replaced by the much more useful Warrior trait that at least allows him to be dragged in via Imrahil among (few) other things. Doesn't fix the fact that he's overcosted and outclassed, but it's fun! Maybe ALeP will do something with the Archer trait someday and save this suffering soldier and his silver friend from suffocating amidst the sea of binder pages.
Noldor decks are well known for their constant discarding, and their cost reduction is no different. The cost of discarding a single card is pretty comparable to spending a single resource, which on the surface makes it look like you have done a one-for-one trade, but there are plenty of ways to swing this trade in your favor.
Want to power up Sailor of Lune? Discard an event as you play him (or any ally) for one less resource. Want to make ally Glorfindel cheaper? Discard him from your hand and then play him from the discard for cheaper. Elven-light wants to be in the discard pile anyways so may as well throw that in too. Anchor Watch, Elwing's Flight, The Evening Star, Skyward Volley, and Veteran Sword-elf all get more powerful when there are copies of themselves in the discard. To close I would like to point out that in an Erestor deck this card is especially helpful since you will be discarding any cards you don't use at the end of the turn anyways, so you may as well chuck 'em now for some juicy cost reduction.
I don't play Noldor decks often but when I do this card is in my decklist. 10/10 would yeet Glorfindel for money again.