I am a huge Stillpoints fan for my speakers but are they effective under components?

I have been using footers for many years. The most significant use IME is decoupling speakers from the floor.
I will never forget putting Mapleshade large brass footers under my $30k, 200 pound Tannoy Westminster Royals. By preventing the bass, etc. from leaking into the floor, it turned my $20k speakers into $30k speakers!
More recently using Stillpoints. But yet to pull the trigger on SP footers under my electrical components. Is it worthwhile to do so? I do have them under my turntable and using the excellent record weight. Understand the physicality there. But more hundreds for my amp, preamp, etc.?
Based on everything you have said I would recommend using them under all of those components. You will probably wind up turning your $150k system into a $225k system. Assuming the same performance ratio improvement as the speakers, of course. 
Uh, oh, don’t anyone tell millercarbon they’re isolation devices.
I got the screw-on versions under my SOTA Sapphire.  I got a trio of the little, flat versions under my Mytek BB.  As veteran reviewer Paul Seydor used to exclaim, "A whole world of difference!"
Consider the Critical Mass Center Stage 2 Footers the best are the 1 1/2 inch however the 1 inch are also a sonic blockbuster.