I agree with your observations with regards to Stillpoints,I have a lot of Stillpoints SS, Ultra5 and Ultra 6 in my system. They are different from CMS Centerstage, Wilson Audio Pedestal or Magico QPods. Stillpoints is ball bearing design, that means it changes the direction of vibration. Vibration is in 3D, Stillpoints restricts vertical plane and only allow vibration horizontally, by reducing the degree of freedom and the damage of vibration is attenuated.
The other footers from CMS, WA and Magico use layers of different materials to damp and absorb the vibration. There is a layer of thermoplastic material to further damp any movement in 3D. The sound is different. Ball bearing footers tend to give sharper image and stronger sound. Thermoplastic material is softer and mellow.
Often the best sound is achieved with a combination of both. I have Magico QPods in my DAC and Stillpoints SS in upsampler.
I always had an impression that when Stillpoints are facing metal surface, like Symposium platform for instance, they sound sharp and artificial.
I have Ultra 5 only under the speakers with ebony wood in b/w them and Symposium
Moved onto Shun Mook GR under some of the components, but that’s a different story all together.