A Wii game in the series was released in Japan late last year, so it is possible that Namco Bandai is looking for cheaper controller alternative rather than creating a plastic drum peripheral that connects to the Wii Remote.
According to the pictures in the patent, the Wii Remote is inserted into a compartment in the drum controller, which is accessed by unzipping a section of the peripheral.
Rather than registering a button press like Namco's existing drum controller, the inflatable peripheral is dependent on the Wii Remote's accelerometer to provide input. Tapping the face of the peripheral registers vibration on the Y-axis, and tapping the side of the peripheral will measures vibration on the X-axis.