The use of filter off behavior is similar to NOS described here:
it's mainly the advantage of not using filter that may introduce artifacts, but they may have other drawbacks.
the issue here is that people does not know exactly how NOS works and may think of broken devices, it would have been better not to have this option, because you can live with every other filter you have in the dac without issues
NOS DAC. Non-Oversampling DAC [Advantages, Disadvantages]
NOS DAC (non-oversampling DAC) is a digital-to-analog converter without an oversampler. Sometimes, the converter doesn't include an analog filter (filterless). Read why NOS DAC is used, its types, advantages and disadvantages, oversampling vs non-oversampling DAC
samplerateconverter.com
it's mainly the advantage of not using filter that may introduce artifacts, but they may have other drawbacks.
the issue here is that people does not know exactly how NOS works and may think of broken devices, it would have been better not to have this option, because you can live with every other filter you have in the dac without issues