It's because with Enchanting, you can enchant them! If you don't use Soul Trap you may obtain Filled Soul Gems from Court WIzards. If you have learned the enchantment, you can put it ON clothing! Plus if your Enchanting level is high enough, the enchantment you place on a normal item of clothing can be stronger than something you can find out in the world. That is so awesome! I always played a warrior/thief type before. I didn't want to use enchanting cause it would mean learning Conjuration.
Then I learned that Court Wizards sell filled soul gems. Meaning, even though they're pricey, you can still get them. (Potentially VERY pricey).
I know I sound excited, but I've played this game a lot before, Like I said, always before I was a warrior/thief type. Then I realized, you can buy soul gems, Then I remembered that Clothing stores sell normal clothing.
Normal, un-enchanted clothing + (enchantment + soul gem) = Enchanted clothing.