When you put the isoacoustic on, the most likely thing that will happen is that the box vibrates much less, when this happens the box no longer emits sound and our senses translate it into a cleaner sound, a frequency measurement will not show that, but if we measure the vibration it will surely come out.Okay, but what about use of isolators?
So does it work? My vote is yes, although if you like the sound that wood, mdf, emits, you may not like isoacoustic.
Perhaps in something extremely solid, like magic M9, the difference is not felt.