There was a piece in The Economist a couple of weeks ago about how some scientists made disposable coffee cups out of bagasse (wasteproduct of sugar production) which were basically as good as plastic on all the metrics GP mentioned but just fractionally more expensive. https://www.economist.com/science-and-technology/2020/11/14/...
Come on, be serious. These kinds of science-y puff pieces come out every day, on all kinds of topics (I can't count the number of times claims around cancer cures, fusion reactors, new battery technology that's 1000x better, etc. are made). This is one engineering group making very preliminary case (that they may have embellished for the media attention - wouldn't the first time - see: recent "life on Venus claims"). It takes time and lots of effort to figure out if this new material can satisfy all the necessary constraints in order to scale to the market.