No matter which backpack from which manufacturer, if they have some accessory straps I usually always get them because they enable you to expand the functionality of the pack in several ways. You could at least strap 1 or 2 big extra items on that thing for sports like e.g. a skateboard or a yoga mat. With some bags you can even use them to compress the bag even more. I just like the extra options that come basically for no extra amount of size. For me personally, basically always an absolute must have on every backpack I own.