You asked if we all should use this and the answer is no. That’s what my answer above boils down to.
Regarding sound: it really depends on your application.
A notch filter can be useful for audio application, if you e.g. recorded something in an environment where there is a distracting noise at a constant frequency or frequency range. Then you can filter that by reducing or even removing this frequency from the spectrum.
It’s the same principle for the Simucube. If there is a frequency that should not be there, you can remove it using such a filter.
In more advanced application you can also use such a filter in images after applying a fast-Fourier transformation. (The latter transforms from the location information into a frequency spectrum, so you can see a spectrum of how quickly pixels change locally.) Then you can remove some of these frequencies and apply a reverse FFT. Removing frequencies here can help e.g. with noise reduction or Moire. Or, in case of video, with flickering.
Generally, though, you want to filter the signal as little as possible, for all of these applications, because filtering almost always results in loss of information. How much depends on the filter type and the parameters.