As a former WDW Resort Front Desk CM who worked at multiple Disney Deluxe Resorts and DVC Villa Resorts throughout my years at Disney, I can tell you that it is actually NOT the same as traditional check-in at the Front Desk, the purpose of Online Check-In is to bypass the Front Desk altogether especially if you have a MB, when you opt to utilize this service the Front Desk will assume that you have opted to bypass the Front Desk check-in process and will not stop by the Front Desk, all of the functions that would normally be done during a traditional Front Desk check-in with a CM (confirm payment, room assignment, etc.) you do yourself during the Online Check-In process, so the human face-to-face check-in element is essentially removed and the check-in communication between you and the Front Desk becomes an electronic process. OF COURSE you can stop still stop by the Front Desk, but procedurally the check-in process has already be completed and it would not be any different from a guest that is already checked in walking up to the Front Desk to ask a question, hence if you are request to change your room assignment it is now a room change rather than an assignment change prior to check-in, this is rather inefficient for both the guest and the resort CMs who are under the assumption that you are already checked-in and well into your vacation. It's like pre-ordering food at a restaurant and then sending it back when it arrives because you simply changed your mind on what you had appetite for, now the food goes to waste and the kitchen has to prepare an entirely new dish for you, this is the same as you using online check-in, arriving at the resort and walking up to the Front Desk to change your room, the resort assumes that you already went to the room which means now Housekeeping has to check the room to see if anything was used or soiled, etc..