The difference being that lockboxes are what I call "non-loot"; they drop in place of something potentially usable, and take up space in inventory. To me, they're an irritant, like a kid getting underwear for Christmas - only the underwear are five sizes too small, and for the wrong gender. At least superpacks had the common decency to only be encountered in the store.
If it'll help fund the game, that's fine, but put them in the store, and out of the way of play. I feel like I've thrown away enough lockboxes to rebuild a Paragon City neighborhood all by myself.