Some people might consider some things included in the "common" classification (not silver or gold), like pieces of heart, let alone heart containers, to be more than just common. Being able to change what goes where for a few nebulous items, like those, or deku stick/nut capacity expansions, would be nice. I certainly think they're more useful than rupees or ammo drops or recovery hearts, but some people might not care to pick up pieces of heart in chests. I don't think full customization would be necessary, since pretty much everything else is fairly obvious where they should go.