Pros: It will automatically orient to either a frontal or rear collision and has tons of contact area with the body. If it's made of even a slightly stretchy material it would also spread the force out over some period of time.
I wish more vehicles had more rear-facing seats. Can’t get used to it without experiencing it throughout life.
Seems like only bi-directional train cars have them, or trams that rarely slow down rapidly.
Metros have them, and in my experience the rear-facing seats are more comfortable, as metros decelerate much faster than they accelerate (or at least in Lille, I didn't notice it as much in three other metros I took).
I had similar thoughts, but that doesn't make it any less funny!
If that hammock and it's attachment are strong enough, it's probably the safest of all the options shown in the article.
It certainly looks a lot safer than the ones that hang your child outside the car.
It's probably same as the ones that hang from the car's seats. Someone hanging it on the window to take a picture or whatever seems likely, maybe even advertised, but that doesn't mean anyone was driving with it that way.