They mitigate the imparting of vibration to the amplifier, which it's components (transistors, diodes, caps, resistors, tubes, etc)
do not like. My guess is the transfomers don't like it much, either.
For example, even the insulator (dielectric) for the wiring can induce triboelectric noise imparted by vibration.
For digital components, for example, the crystal oscillators in the clocks are VERY sensitive to vibration.
You should also elevate your cables of the floor, as well, in particular, the speaker cables (SPs) and power cables (PCs) are sensitive to floor-borne vibration. I used think cable elevators were a bunch of hoo-ha. Boy, was I WRONG on that one....yikes.
Cable elevators for SPs as shown...
With respect to components, my Lumin P1 shown (L middle rack shelf) is resting on it's own footers (Lumin is good at this) on a 3-layer IKEA Aptitlig bamboo platform resting on Herbie's Audio Labs Tenderfoot footer. The Aptitlig cutting board platform has bamboo with the grain running in three alternating orientations. Turns out bamboo is one of the best materials for damping vibration, and the IKEA Aptitlig cutting boards are only ~$20/each. Same applies to the Altaira stack that is also on it's own Aptitlig platform. Lots of audio guys use Aptitlig boards as a very cost-effective vibration damping platform. The Altairas also have Shunyata's optional SSF-38 footers installed, which have exceptional
impulse transfer speed, so they transfer vibration
away from the Altaira VERY quickly, before it can have an impact on audio quality. Thes are the best footers for Altaira.
The Constellation Inspiration integrated on the rock maple platform rests on the HRS Nimbus couplers, which are
very effective at damping vibration.
