To play devil's advocate, as a species we've spent the vast majority of our existence sleeping on the literal ground. It seems plausible there may be some adaptation to the electrical properties of being at the surface vs ensconced in synthetic materials above it.
Granted there's no evidence for that as of yet, but there was a time when fiber in food was reasonably seen as just inefficient waste that couldn't be digested and so had no benefit, that's part of how we got Wonder Bread and the obesity epidemic.
The only possible way for this to do anything measurable if it somehow reduces the 50/60Hz AC hum impressed on your body. But either way with the wavelength of 60Hz in meat being like earth sized I dont think any significant electric fields will arise within two points of your body to do anything meaningful (as long as you stay AC coupled, if you DC couple to mains health effects are guaranteed).
To play devil's prosecutor, charge resides on the surface of an object, and the electric field inside is zero.
> It seems plausible there may be some adaptation to the electrical properties of being at the surface
This is like saying it’s plausible that wearing a bracelet with a small magnet in it will have health benefits. It’s pure woo. There’s no reason to believe this from a scientific angle. It’s perhaps not impossible but it is certainly not plausible.
> there was a time when fiber in food was reasonably seen as just inefficient waste
When was this?
> as a species we've spent the vast majority of our existence sleeping on the literal ground
This isn't true, though. For the majority of human history, humans set up grass and leaf bedding atop campfire ash, using animal furs for additional insulation when needed. Ash and leaves are electrical insulators.