As a more pragmatic matter, as far as handloads go - for defensive use, the ammo has to be 100% reliable. To me, that means new brass, free of any nicks, dents, or burrs from previous firings. You obviously can get it with brand new brass, handloaded, or buy new factory ammo.
You could also argue, it's hard to find good defensive ammo for some cartridges, hence "I had to load my own for this gun"
