Overshadowed by Defender of Rammas now in most cases. However, plays well with The Eagles Are Coming! and Support of the Eagles. Its discard might be desirable if you're using Eagles of the Misty Mountains to build a super ally. As one of just two cheap eagles (Vassal of the Windlord,) you need these to build a deck around the trait.
Ally. Cost: 2. 0 0 4 1
Winged Guardian cannot have restricted attachments.
Forced: After an attack in which Winged Guardian defends resolves, pay 1 resource or discard Winged Guardian from play.
David A. Nash
The Hunt for Gollum #4. Tactics.