Basically, these machines are modern versions of the old Bulldozer bender.
The differences between one of these and a press brake are several- a press brake is designed to bend flat sheet, so its designed to handle big sheets the easiest way- flat.
A Bulldozer is horizontal, so long things dont fall out of it, and is usually open throat. And these bulldozer machines are able to take a wide variety of tooling- if you look at some of the setups on the above links, there is dedicated tooling for radiuses much larger than a press brake, which is essentially a single point bend, can do. Plus, scrolls, round bar, multiple curves in one bend, and lots more. One push U bends, as opposed to two bends to get the same result. Railing pickets that are 2 feet long, and have in them, all done in one bend, curves, sharp angles, reverse bends, and so on. Hooks, Loops, and other odd shapes. Special tooling for angle, or channel, or hex, or square bar.
I would agree, one bend in 1/4" x 3" bar doesnt need 40 tons. But a two foot long profile in 3/4" square bar, all in one push, probably does. Another poster right now wants to bend S hooks in 1 1/4" round bar- a machine like this would do it.
Its good for some things, not as good for others.
Me, I like to have 3 or 4 ways of doing every job, because I inevitably come up with oddball materials, strange shapes, and unusual needs. I have angle rolls, plate rolls, hand benders, hydraulic presses, a power hammer, and various other means of bending things, and one of these would supplement what I have, and give me more options.
But certainly, not everybody needs one.
There is still a heckuva lot you can do with a hossfeld, that, fully tooled, brand new from the factory, is under 3 grand.