Why does the AssetBundle needs the assets to be present in the folder?

Using 5.3, been trying to make asset bundles work for almost 2 weeks, I still don't understand why, if you delete the assets the asset bundles stop working, doesn't it makes the asset bundles useless? I mean, why do I need the assets along with the asset bundles, I could just load the assets normaly if I have the assets in the asset folder, makes absolutely no sense.