Not the original author of the comment but I share the preference. I hold my phone often by the sides; the edge of my palm is a bit higher than the edge of my phone and is not supporting it from below. A bit like this but without the assistive strap and my fingers actually wrap around the phone a bit more: https://images.app.goo.gl/oxvXQRVBg38oTjnH6

My hands are somewhat skinny so the meat of my hand doesn't interfere but I think my phone case also has to do with this. My grip seems rare, I couldn't find images of it.

I can't use my pinky as a hard stop always, because if I do it for long enough, I'd get some pain in my joints.

I switch between grips depending on what I do. My texting grip is the one people usually have and I switch to it by pushing my phone with my body to guide it down my palm.