I have seen those type of things recommended for isolation of speakers and subs, but the thing is those are intended to damp much heavier and much higher vibration equipment than any speaker or subwoofer. Those might be better than nothing, but they might be too stiff to be optimal for audio equipment. I don't think mechanical isolation is going to do any good with audio equipment anyway, except in a few special circumstances.
I haven't tried them for that but have seen the recommendations many times while I was deciding on my strategy for dealing with my spongy suspended floor.
I totally dig your instinct, though!
I do like my experience with the Soundpath feet from SVS. Just can't abide recommending them for the cost. I found mine, third party from a "fire" sale and rolled the dice. Glad I did.
Strangely, and separate from this, I did order a set of those diversitechs to put under our washing machine which will vibrate half the house on its spin cycle. It really interrupts my own vibrating of the house with two X-13s!