Sure looks easy and foolproof.
It's a good tool. It forms a nice tube.
That said, I think it's helpful to look through reference books that have good photos and pay attention to the hinge tubes. There are some differences in how they were made. So, I don't think a bending jig like this is always the best tool for the job, at least not if the builder is trying to reproduce the look of some particular originals. Some antiques have a hinge tube like what this tool will produce, with a tight bend from the flat to the tube. But some others were quite obviously made in a more relaxed manner. I've experimented some with how to make different styles of tubes, and it seems pretty obvious that some were just formed with a vise, anvil, and perhaps a wide punch, and no special bending jig.
So, I like this tool, but I wouldn't necessarily use it on everything. People's philosophies on this kind of thing differ a lot. Some guys like to try to "improve" the originals, so they like the idea of improving the hinge, etc. I generally prefer the idea of trying to mimic the techniques used by a particular old builder or school. It's just a personal preference. Neither philosophy is right or wrong, but they can lead a builder to produce very different results. ---Just some thoughts.
