The reason for padding inside shoes is to distribute the pressure of the closing mechanism (laces, straps, ratchets, boas...). If a bare carbon shoe is custom molded, it will distribute pressure evenly across the whole top, bottom, or side of the foot. Better fit means less padding is needed. A perfect custom fit virtually eliminates the need for padding. At most you would need a slim sock to accomodate the small movements of the foot as you pedal.
Adam Hansen has ridden shoes just like this for the length of the Tour de France. In fact, he makes them for himself. At that level, he could ride any pair he wants, but chooses a design like this.