I would like to comment about on the Purple Heart story. While everyone recognizes the medal, in many ways, it is the certificate that is more important. Certainly, the certificates are more rare (much so) than the medals. The medals are just about indestructible so they will survive fires, flood, and even just poor handling over the decades. The certificate on the other hand is made of paper and fragile.
Additionally, the certificate has the full identity of the recipient of the award and details of the act in question. During World War II, expedient certificates were sometimes issued because the official and fancy certificates printed by the Bureau of Engraving and Printing were not available. Sometimes the person later received the more elaborate certificate, other times not. As BEP products, it is my opinion that the certificates themselves are numismatic items.
Good point about the certificates. I have to agree about their rarity and importance. I've seen several Purple Heart medals, but I've never seen a certificate. Often people will frame the medal along with a picture of the soldier, but I don't recall ever seeing a framed certificate.