So... Magic Swords, Magic Swords, Magic Swords, Magic Swords, Magic Swords and Vorpal Swords.
Classifying swords with slightly different types of magic differentlly is silly enough, but "elemental swords" as one thing and then "holy" and "dark" separately again is utterly pointless.
Well because holy isn't an element, it's divine power, and "dark" is referring to the cursed nature, not the darkness.
If you think about it the other way around, it wouldn't make sense for miracles performed through divine intervention to be classified the same way as a fireball spell would. One requires a literal god the other has no particular condition.
If light magic exists as elemental magic, it'd be manipulating the element of light, not the power of the goddess.
Similarly, you wouldn't classify curses, which have different rules from elements, as elemental.
Now getting to the classification part. From a practical standpoint, it does make sense to classify different types of magic differently. From an Earthling point of view, magic is unordinary, but from a local point of view, magic has always existed. Who wouldn't like more precise knowledge of what subcategory a sword imbued with magic falls under? You have to remember all these types have completely different behaviors.