Set dynamic Options array in woocommerce_form_field

You can use array_flip to set all the keys to the values from $dates, but if you want the value to be passed through translation function you can just build the array using foreach

$options_dates = array();

foreach( (array) $dates as $date ){
    $options_dates[ $date ] = __( $date, 'wps' );
}

Then just set 'options' => $options_dates,