Does a Subwoofer Make Spiking Redundant?

" bolt your speakers to a concrete floor" - this is completely wrong.

The whole purpose in "decoupling" the speakers, and sub, from the floor is to minimize, or eliminate, the vibration from reflecting back into the speaker. This reflecting vibration muddies up the sound of your speakers. Eliminating the reflecting vibrations tightens up your bass, and the speakers’ sound becomes more clearer. Bolting the speakers to the floor will only insure that the vibration passes from the speaker into the floor, and reflecting back into the speaker cabinets.
Spiking the speakers will only minimize this vibration. The best ways are to use springs, as suggested, seismic podiums, or energy dissipating pucks.

My system is on the second floor. I added some of the mentioned Nobsound springs to subwoofers and noticed my kitchen lights (one floor bellow) don't rattle as much. However, I feel as though my subs lost some punch.  

i read a lot of this and find it confusing. certainly contradictory ( what else is new?).
There are many theories, but the most reasonable, to me is that we want speakers to be totally immovable - a solid, stable surface for drivers to push against.  If they resonate, they modulate the drivers - especially the midrange and tweeter where the wavelength is smaller relative to any vibration or rocking motion.

Spikes are often used to cut through a soft, unsupportive material that will allow the speaker to rock, such as a carpet.  The subwoofer OTOH adds lower frequencies and is mostly an orthogonal choice.

Now, a spike on a hard surface is a different animal and I would tend to not use them. Those spikes minimize the surface area (which in the newtonian sense of friction m,akes no difference), but also increase the force per unit area meaning the connection will be more fluid due to material shear. In theory. This is why car tires are non newtonian as well (wider is in fact better).

I prefer mass to stabilize the speaker (big, heavy speakers on a solid 3-points so they don't rock) and maybe as one suggested actually isolating the speaker from floor vibrations especially if its a live floor. I have not experimented with those.

Acoustic Science Corp and Acoustic  Fields have Subwoofer Platform Traps 18” off the floor for more than one reason. 

My speakers are spiked, heavy carpet, pad and plywood underneath. 
   If I place on rug, they are tipsy. 

What else you recommend?