Spikes contrary to popular opinion do not decouple and will allow vibration to pass in either direction.
Yes, spikes are coupling devices. This has been discussed many times in Audiogon threads. Yes, they are sometimes discussed interchangeably (and erroneously) in threads about isolating devices, so the misunderstanding perpetuates
That said, coupling devices like those sold by StarSound Technologies (I can’t recall their new company name), are very effective producing wonderful sound.
I have owned Townshend and StarSound loudspeaker platform products. The effects were equal to my ears.