If there is any real advantage to pellets to offset the expense, it might be tied to the substance of this topic. Although I don't have any scientific basis for this opinion, I would think pellets could be left in a loaded gun without issue considerably longer than loose powder. And, of course, when it comes time to unload a gun that hasn't been fired, the pellets just fall out the breech. I even save them in a separate container marked "used pellets"- use them for practice loads. Never had one not go "bang".