One of the many interesting wrinkles implied in OD&D is that all magic swords possess an alignment and have the possibility of intelligence and special powers above and beyond the bonuses they provide when wielded in combat. Given that no subsequent version of D&D follows this interpretation, I'm not as convinced as some that it was intended. Rather, I think it's implied that magic swords alone may possess alignment, intelligence, and special powers, but, as is often the case in the three little brown books, the text is written haphazardly, thereby leaving it open to individual choice as to how to read it.
I have no problem with this particular interpretation and I think, like limiting the use of magic swords solely to fighting men, it adds some nice flavor to OD&D campaigns that employ it. I've been kicking around the idea of adopting it in my next campaign precisely for this reason. As I've explained before, neither magic nor Nature is personified, the former simply being a feature of the universe and the latter being the "stuff" from which the universe coalesced (there is no Creator in my current cosmology).
Interactions between magic, Nature, Chaos, and the gods (at least some of which owe their own existence to a process similar to the way the universe formed) has given rise to a variety of elemental beings, not all of which are as insensate and uncaring as Nature itself. I'm currently toying with the notion that the process of metalworking, which involves (to some degree) the interaction of all four elements inadvertently gave rise to a "fifth elemental" -- spirits that are sometimes drawn into crafted objects, endowing them with magical powers and, in many cases, allow the spirit to exercise its own intelligence and will.
The hows and whys of the process I prefer to keep strange and mysterious, including why it is that these metal spirits seem to manifest most fully only when drawn into swords -- thus giving rise to their more common name: "sword spirits." But I very much like the idea that the fashioning of magic weapons isn't simply a matter of a magic-user deciding to do so by following some hoary formula that always results in a sword +1, +2 vs. lycanthropes. I want magic weapons to be, on some level, accidental in their origins, something beyond the ken of men, elves, and even dwarves (who were probably the first to notice the phenomenon). It makes magic swords special and a little bit dangerous and that's a good thing.