Spirit monsters you control gain 500 ATK and DEF. If a face-up WIND monster(s) you control returns to your hand (except during the Damage Step): You can add 1 Spirit monster or Ritual Spell Card from your Deck to your hand. You can only use this effect of "Shinobird Power Spot" once per turn.
Good attack and defense increase for all spirit monsters.
Can get a spirit card from your deck or a ritual spell card.
Second effect only works for WIND monsters that are returned to your hand but not as a result of battle.
I think he is referring to how you can fetch Asura using this card, then proceed to demolish everything in sight next turn. Otherwise, yea, there is a reason it is called "Shinobird", because they are current the only WIND/Spirit monsters in the game. That's not to say Mist Valley can't push this card further.