There's another reason to have multiple accounts that's valid: companies. It's possible for members to come together as members of a company, and then create a company member name. This isn't particularly useful if the company is composed of three or fewer members, but if it has, oh, say 10 members, then it becomes an issue, as the store system only allows 3 folks to be listed in a product at one time.

thou and I, my friend, can, in the most flunkey world, make, each of us, one non-flunkey, one hero, if we like: that will be two heroes to begin with. (Carlyle)