The point to me is that before they ate of the tree, they were dumber or naive and innocent. It wasn't that they put on clothes so they wouldn't sin. It was just that they noticed their nakedness for the first time and for some reason got embarrassed. So they made clothes.
In Paradise people would still have their memories. They would still know right from wrong. So they would still wear clothes. Only if they magically reverted to the naive and dumb stage would they stop with the clothes.