Survival for dogs must involve catching it in his teeth first. Once it's captured, securing it with his paws is less of a survival problem. A bone provides little in the way of nourishment or utility: That a bone might slip away isn't a great loss.
Humans dont grasp things? BTW, a scotch pot cleaning pad has friction strips, too. Some designer someplace...in some soap lab...noticed an obvious idea.
And...
"...the last I checked humans grip a far greater variety of objects (large and small, coarse and smooth) than do apes..."
The same "friction ridges" that appear on your fingers and palms also appear on your feet.
What were we humans supposed to be grasping with our feet?
Traction.
It’s why they put spikes on track shoes,
and interestingly, very similar little split lines on new all-weather tires (for which I paid about $550 at Firestone :>)