Why don't radio-controlled clocks with analogue displays have any setting stem?

Radio-controlled clock movement automatically adjusts its hand positions.
A microcomputer embedded inside the radio-controlled clock detects the positions of the hands and synchronizes the hand movement with the internal clock of the microcomputer. If the hand positions of a radio-controlled clock are moved by a setting stem, which is used in the movement of non radio-controlled clocks, discrepancies between the hand positions and the internal clock of the microcomputer will occur, and the clock will not be able to display the correct time.
Therefore, radio-controlled clock movements have no setting stem.

(Note): The above information applies to the members of
the Japan Clock & Watch Association and their products.