Nikon DSLRs have this 3D tracking feature in which you select an object to keep in focus and it refocuses based on its movement inside the frame when it hits the focus points. And when the subject exists the frame and re-enters, auto-focus comes back. 51 focus points may seem like feature creep, but as I said, it's freaking awesome when shooting moving targets like birds.
Even for subjects that are still, like for portraits, you have a lot more freedom for composition as you just select the person's eyes and then you can move around while the eyes are kept in focus.
Of course, you can do a good job with a single focus point, but professionals and amateurs need predictable results, because good moments for taking photos are rare and you don't want to screw up because your camera wasn't properly focused.
That's why I can see partly the utility of this technology here, but on the other hand I can see serious problems with it too, the biggest one being that for most people quantity of photos trumps quality. Another problem that I can see is the one I mentioned above; precise and predictable focus is not that much of a problem with modern cameras. And yet another: mega-pixels and quality of optics count a lot. Well, maybe once passed a certain threshold, the there's less ROI from a higher MP, but still, under 6 MP a camera is only usable for publishing on Facebook.
My consumer DLSR has 4 FPS and I don't worry about focus as I just continuously shoot like 20-30 pictures in a row to make sure one of them is good, and usually one of them is.