Our code is not released yet. If your data is captured without occluders and in RAW format, you don't need the enhancements we propose :). NeRF can do amazing things with clean data!
I just saw the NeRF demo video, it's amazing. If its results are this good, why is photogrammetry software not basically perfect yet? It looks like they can generate models with vast amounts of detail.
Not the author (but I read the previous papers and the code), the simple answer is that it's still very costly in processing power. Think a few hours on good hardware for a set of pictures.
Note that the results are still very impressive imo, this is still early research phase.