Found one on Amazon so I dodge Google's exorbitant plastic markup, and it is a relatively minimalist wrap that smooths out the camera bump and makes it more grippy in hand, in pockets, and on flat surfaces.
The behavior of those slippery phones in pockets is almost the bigger gripe to me. Like they are a new class of motion amplifier, trying to rotate and squirt their way out at the slightest twitch.
I would never use a case with a phone of any sort. I don't like the extra bulk, and the friction they add is annoying.
Meanwhile I never use a tablet or kindle device without a cover.
The curvature on the back of those is such that it's harder to rotate into a position so the thumb can hit the right button than a flat surface would be.
It also means that resting it on the arm of a recliner produces about the same result as just dropping it into the void to begin with: It's going to wind up there either way.