Why would passports be stolen?

My father was stolen his passport during a trip to Europe and he finally had to deal with the hassle of dealing with the US Embassy and all …

But I am really puzzled. Why would anyone want to steal a passport? You can not travel with, because CLEARLY, you are not the person pictured, and it is more than likely that this damn thing will be reported as stolen in a few hours, which would make it useless anyway !