For an Enchantment that only costs 1W to cast, that's already pretty good. However, it also has a second ability. For 1W, you can sacrifice a Spirit and a target non-Spirit creature gains indestructible until end of turn. Being able to save some of your best creatures from board-wipes at the cost of Spirits that would be lost anyway is very helpful.
Overall, Spirit Bonds is a very solid rare Enchantment that is very playable in a wide variety of Commander decks. Agressive mono-White Commanders such as Jazal Goldmane, Radiant, Archangel and Lin Sivvi, Defiant Hero have made decent use of this card. Other Commanders that have used Spirit Bonds include Alesha, Who Smiles at Death, Brago, King Eternal, and Teysa, Orzhov Scion, among others.
Spirit Bonds hasn't really seen much Constructed play, however. There was a Magic Online Standard deck in November 2014 that did run two copies, a WBR aggro brew that you can find here. There have also been some rogue budget Blue/White Heroic and White Weenie builds that have also run two copies. During its time in Standard, it was a good card that just never found itself in a strong enough deck to be worth much. If you're building a Commander deck with one of the aforementioned Commanders, however, it's a card to keep in mind.