Your concerns are valid, but not based, I am guessing, so much on experience as what you've heard, seen, or thought.

What I mean is, you've never tested how close you can get a tent to a fire before it melts or burns up, and you've never had one melt or burn up because you got it too close.

I haven't either. I have worked with fire and extreme heat a lot, so that experience is an advantage I suppose. You tend to learn what is a potential hazard and how to deal with it. For example, I've used visqueen as a spark shield when welding and cutting steel. It actually works really good for that. And I have lived a lot of years where campfires are a part of life. I've melted a few soles getting my feet too close to them.

Personally, as far as fires and backpacking go, I'm more interested in how small a fire I can use, and how long I can make it last without fiddling with it. I haven't tested that yet with that shelter. I did build a long fire, like that suggested in the link to the video skcreidc posted, and it wasn't a very big one, but I still don't know how small of one I can use.

I think that if you did take the time to play with this concept, and as you've said, "don't build your fire so close to your tent", and make it a small fire, you'd be more comfortable with the concept. Maybe not comfortable enough to fall asleep in it, but more than at first glance at least.