We got them to add some really positive footholds for our toddler. They are pretty big, so some of them I set as knobby crimps on our vertical wall. I've only used them as feet on the 15.
We've only set them in their most positive orientation, but even flipped over they are pretty big, if a bit smear-y. If you only have lower angled walls and want something to train precision maybe look elsewhere, but if you're looking to fill in volume with solid feet, these are a great option.