This high school "senior exit" video from the grandson of a longtime body powered hook user comes to a conclusion that many of us here in the US have: that body power in its current form is superior to powered (often myoelectric) limbs, and is a great effort. Along the way, the author makes a few mistakes that are worth pointing out. Depending on the features, body powered limbs can be more expensive than cited (at least double the $4000), as can many of the powered limbs. Some of the research limbs featured cost in prototype form as much as $850,000, and aren't generally available. While targeted muscle reinervation (TMR) surgery is required for some forms of control, it is not required for all forms. The DEKA Luke arm (not featured, as far as I could tell), for example, can be controlled using a foot controller as well as traditional or pattern recognition myoelectric control.
The borrowed egg cracking scene using the touch bionics hand is certainly impressive, although I believe could be repeated by an experienced body powered voluntary closing or opening device user. Of course the question would remain in either case "why?", as most unilateral users would simply use their sound hand. A hook user wouldn't need the bottle opener to open the beer in the other borrowed scene, but the real substance of this debate should ignore party tricks of any kind, and focus on acceptance and on real activities of daily living (ADLs). This is a shortcoming of the debate in general, and the images selected for promotion of prosthetic devices are in general a misleading sample of real ADL tasks. The video does a good job of showing hook use in a number of very realistic situations.
Despite its flaws, the video is well executed, and it's refreshing to see something available that counters the common narrative in the media that either powered arms or 3d printed hands of one kind or another represent a sea change for arm amputees. This is a topic of discussion that would benefit from a more balanced representation on behalf of what most people have no idea is the true current state of the art--body power, as evidenced by Bob Radocy's victory with a body powered TRS Grip in the recent "cybathon."