I'm sure you know exactly how much of which filter to apply for similar results. Laymen like ourselves will need a lot more trial and error. Their contribution here is to provide a push-button, automated mechanism.
I would have probably also tried something simple and given up due to the noise. So this is definitely interesting.
What you are describing is usually called automatic tone mapping. This is basically noise reduction and possibly color normalization from brightening a dark image. Them showing their black image as the starting point is silly, because jpg will make a mess of the remaining information. What they should show is the raw image brightened by a straight multiplier to show the noisy version that you would get from trying to increase brightness in a trivial way.
So presumably this neural net more or less does it for you.