This is certainly interesting especially since a lot of us are working from home and ergonomics improvements are welcome. But Lying down is good especially for those with spine problems but I find it problematic to work in more or less a supine position. Blood pressure lowers as compared to the sitting position and this can have effects on work performance and even induce sleepiness. Of course if one has constant back pain this tradeoff might be worth it. Having said that, I sometimes work from bed and while it is comfy for a while I find that it weakens my body somewhat and try to avoid making a habit out of it.