There is really no difference if you are going to be filling them with the same flavors. The benefit would be for using DIY
juice in flavors we cant get our carts in. I have 10 of the blanks for just that reason. You should be able to refill them just like your used ones and just as many times. They also wash out the same as my pre-filled carts. So at least for me the only benefit I see is being able to load them with my own juices and not have labels with the wrong flavors on them.