While I agree with other commenters here that this setup probably isn't a good idea for most people, I want to go out on a limb and say it seems to me the author may have good reason to have undertaken such a project (he specifically mentions that this article is NOT about his motivations). Specifically, just profiling based on the apparent age of the gentleman in the photos, I would not be surprised if this reason was some sort of injury, arthritis, or similar source of pain caused by ordinary sitting-at-a-desk posture. All that is to say, good for him for making a thing that seems to work for his needs, and shame on people jumping to poo-poo this because it's not solving a problem they personally have.
I've tried all the setups at this point, including the supine one. It has plenty to recommend it in a limited, mostly consumptive role; many people sleep a whole eight hours in roughly that position. It does tend to get in the way of typing although a fully split keyboard can address that.
But my everyday work is now done at a floor table. This posture brings a different level of activation energy, and it lets me keep moving around which is a clear advantage over most. It can present some of the same stresses as chair seating but it has more opportunities to relax. And unlike the standing or treadmill desks it easily works on a budget too - tape up a cardboard box and weigh it down and you have a temporary desk setup that will support most equipment. For a better surface with a finish and leg room, Ikea provides options, or you can get more specialized folding floor desks with angle adjustments and drawers off of Amazon.
Using a floor table is my favourite one so far, though I haven't tried a reclining setup yet. My only issue is the lack of back support if I want to lean back.
Personally I realised that trying to economise too much on desks is actually kinda crazy when you work out how much time one spends using the desk (like a mattress), so I went and bought a standing desk which is definitely easier than stacking cardboard boxes etc.
i assume you mean sitting on the floor and using a shorter height table as a deak. i would love links to Ikea options. i can't even think what you would search for to find such a thing!
Definitely. I had to go in for a back operation some years ago, after which I wasn't allowed to sit or bend down to pick things up off the ground for three months.
Beforehand I reworked my whole house to lift everything up and to make arrangements for computer use/entertainment while lying down.
I used an older iPad as a remote screen with a sturdy heavy use bendable arm to hold it, while just putting the keyboard on myself with the mouse down next to me which worked well enough. His mounted keyboard would probably have been an improvement, but using the mouse next to your body on a sturdy surface+mat worked really well.
I also made a temporary standing desk using boxes of paper to lift up my screen, keyboard and mouse, so that when I got tired of lying down I could stand for a bit.
All in all it turned out to be a really cheap and fast to implement solution that easily worked for the 3+ months.
I've done something similar for a while due to injury. I wouldn't recommend it. If you work 8 hours a day like this and sleep 8 hours a day, all while lying down, you'll waste away very fast. Sitting or standing might be uncomfortable but it's preferable. Do physiotherapy and try a standing desk or something.
