The Parcel Hook is useful for several things, such as:
Parcel Carrier: an easy way to carry your packages if they are wrapped in twine;
Para Cord: works great to pull complicated knots through nice and tight;
Untying things: if it can tighten stuff it can pull it apart;
Tent Stakes: this will help you pull out those tough tent stakes;
Zip Line: if you are stranded on a roof top with para cord and your SAK you are in luck. Just lasso off and slide down;
Storage Space: put gizmos and stuff under the hook;
Self Defense: just shove the hook into an attackers mouth and hook 'em like a fish on the cheek and pull until they cry uncle;
Groceries: an easy way to carry your groceries for an extended walk to your car or home;
Cooking: lift up boiling hot pots, pans, and lids without burning your fingers;
Painting: helps carry uncomfortable paint cans with metal handle;
Electrical work: if you are placing a new switch through sheet rock simply insert the hook and pull your string/wire/chain though the hole;
VCR: if you still own one of these it will help pull that stuck video tape out;
IV Holder: simply wedge the SAK handle with the hook hanging down and attach an IV bag;
Boot Laces: helps tighten boot laces (refer to para cord);
The list goes on and on