This is really, truly impressive. I'm tempted to invest some money in one of their plans for further experimentation; I think this has the potential for better upscaled backgrounds than we've ever seen before. No substitute for the work being done on redoing backgrounds from the ground up with fresh scenes and renders, but I think this could definitely be the best stopgap until that is finished.
Edit: Their pricing is wonky, though. A monthly plan is such a ridiculously better price, I can't fathom why someone would pay their much higher per-image pricing unless they need very few images processed over an extended period of time.