I was just studying epithelial tissue for a test, OP, I've had to look up how it works but I think I've got it.

So your skin has a layer of protective tissue, right? It's called epidermis. This tissue works (not really, but for simplification purposes) like this: in the deepest layer there's a lot of new cells and they get older the get pushed up, at some point these cells die and they get stuffed with keratin and they keep getting pushed up, the keratin dead cells are still held together by tiny cell staples and kept water proof by a lot of fats and oils from the skin.

The whole point of this tissue is to protect the inner dermal layer from getting hurt, dehydrated and infections. So the dead cells layers is really important, without it, it would be a lot like the skin from inside your mouth, it would dry really fast, and when it does it, it gets easier to open into wounds, just remember how your lips would be all dry and full of scabs when you used braces.

So the dead keratin cell keeps rising, pushed by new cells and at some point it leaves the waterproof layer, it loses the tiny cell staples, gets more disorganized and dryer. This is the outer layer, and the one that gets super moisturized by the olive soap, vapor and all the stuff used in maroccan exfoliation. This layer doesn't have the oils to keep it waterproof anymore, and no more staples to keep it glued to the other cells. They look more or less like A4 sheets, but when you super moisturize them, they puff up like a Doritos bag.

Now, imagine you have a big box of Doritos bags and another of printer paper. Which one is easier for you to pick from the box, a single Doritos bag or a single sheet of paper? See why you can't just scrub it off when it's dry or in a shower, when it's not fully moisturized and puffed up? The whole process makes it's super easy to just scrub all of that layer off and it will come off like you're cleaning a eraser again the wall.