in your first pic there are a couple features that I see, a notch and a lip. I imagine you could just put a pipe there and pull. But as to whether one could bend a typical 3/4" pipe that ways, seems wildly optimistic to me, unless they mean just conduit or something. And I would expect kinks. All pure guesses, never used a pipe vise that way.
On my Rigid and others with the chains, there are posts that you use for bending pipe but again I can only see doing that with small tubing, like brake lines and the like.
Anecdotally, I used my new (to me) Columbian pipe vise yesterday to hold a shaft I need to remove pillow blocks from. Well, it held it just fine but also promptly put noticeable marks on the shaft due to the very sharp teeth. Gotta play easy with that one... At least the weld held, that's something. The other good part is that I held the Columbian with the Prentiss, so doubled the fun!