@esthlos13, my understanding is that the purpose of spikes is actually to *couple* the speaker to the floor. The spikes pierce through the carpet to reach the concrete slab underneath into which they transfer their energy. The idea is that a giant concrete slab won't resonate much and is therefore good for absorbing vibrations. In contrast, when coupling a speaker to a wood floor, the wood would be too excited by the speaker vibrations, and the resonances created in the wood floor would negatively interact with your speakers.
Another way to think about this is that with wood and tile, you only have one choice--to decouple. But with with a cement floor, you have another option--to couple.
Another way to think about this is that with wood and tile, you only have one choice--to decouple. But with with a cement floor, you have another option--to couple.