I have the straps on the bows but do not need them as my vinyl cover has its own straps on the inside that connect to the outside as there is black plastic circle pocket with a loop for them to clip to.
The front of the cover is strapped to the front of the bed and the 2 front corners strap to the corner of the bed side. The back has 2 straps on the inside that go around the bow. Different straps and buckles than the ones to roll it up. That is enough to hold the cover down with the sides and back rolled up. I have traveled down the interstate at 60 with it rolled up with no issues plus the cover has some weight to it already.
Trick I learned the hard way is roll up on the inside. At first I rolled to the outside and it does quite a number in retaining water and dirt and leaving stains if you leave it that way. During the summer at the Boy Scout camp I keep it rolled up for 2 months at a time. The new "trick" is roll it to the inside and there is no pocket to hold water and dirt. The straps on the inside will work either way and they will cinch tight. Same thing for the rear flap.
I have seen another brand of cover that has the loops on the outside sewn in but not the black plastic pockets.
