I liked the way Children of Earth was presented. It was a story that covered five days, one day per episode, and it was aired over five days, so it was more or less in real time, which was interesting. And it made it more intense than if it were spread out over five weeks.
The BBC does this not infrequently, but it's usually with more mainstream fare, such as crime dramas. IIRC, this was the first time they did it with a sci-fi series, certainly the first that I remember.
And yes, the premise of COE was helped greatly by this airing.