I think that backpacking holidays and package holidays are really different ways of living your vacations.
They can be distingued since the care they need in their organisation: you don't have to prepare a package holiday, while you have to dedicate a lot of time to prepare the backpacking one. Indeed, if you choose to travel with a rucksack you have to think about all the aspects of your trip. Before the departure, it's important to know very well the itinerary of the trip and the places in which you will eat or sleep, and it's foundamental to choose a right equipping, that includes all the things that coulb be necessary in whatever situation.
On the contrary, in a package holiday everything has been already organised, so you have to worry about anything; but it's also true that you can't choose all your activities, beacuse they have been prepared by other people.
The purpose of this two kind of holidays is generally different: in a package vacation you usually want to relax or have fun, while in a backpacking holiday you usually do a lot of physical activities, as hiking in the mountains or visit cities on foot.