Trucks should have the capabilty of towing. A truck w/out towing capability is like having a spare with no jack.
Sure you can still get the tire changed, but you'll need someone elses help to do it.
The towing package is nothing more than a 2" receiver bumper, attached to the chasis. If you want to utilize the feature, you can take your pick of the towing device to slide into the receiver.
Without one, the truck is nothing more than a very big car.

A factory installed towing package gives you a stronger tow attachment, and all the wiring in place. All you have to do is plug in the trailer lights, and go.

Also, it is a great device to have for rear crash protection! Ever see a car that rear ended a vehicle with a towing ball, pintle hook, or any other tow attachment? The vehicle that gets hit just drives away. The other one is towed away.