exerts numerous benefits that a simple google search will indicate. BCAAs, while technically a component of protein don't quite have the same effects. BCAAs can be used to stimulate protein synthesis and inhibit muscle catabolism.
supplementation is not necessary as one can achieve appreciable amounts via diet. If fish is not a component in your diet then supplementation is in order.Free form BCAAs cannot be obtained via diet, at least in the appreciable quantities so supplementation is required if you desire their effects.