I bought these as feet for my vertical wall. The variety is great for footwork, from solid to thin edges. Some might be able to use any of these for crimps too, however at my level, I was only able to use about half as crimps when I got them. That said, its been tons of fun slowly switching holds from the "foot only" side to the "crimp or foot" side.
Some of these holds are now my most favorite crimps.
Good for very difficult 2-3 finger thin crimps, or footholds.