I hear speakers sounding their best when they are rigidly mounted and supported.
I would only consider isolating the speakers from the floor if that floor were audibly excited by the speaker cabinet vibrational energy.
My current setup is large stand mounted monitors decoupled from a high mass rigid stand that is spiked to a concrete floor through carpet.
Bass is deep and ell defined, midrange is super clear and transparent, the floor does not audibly respond to the cabinet's vibration energy.
If i had a wooden suspended floor I might consider isolating the stands from the floor- it might provide the best possible sound but would be a compromise compared to a more solidly mounted system on a solid floor.