I’ve got them and would buy again. The only time I put any blocking down is when the site isn’t level from side to side. I do believe when only the Snappads are used without blocking they help keep the rig more stable when walking around inside.
I’ve had them on my 5er a couple of years now. Great investment, I no longer have to deal with jack pads in areas that the jacks may sink into the ground or paving.