Well concrete is not waterproof (generally) so they are technically also using the form as waterproofing. It's pretty clever IMO but you'd need rebar at the very least for any structure worth building...
I’ll take tyvek and wood :)
Sustainable, innovative building structures that don't require energy-intensive and corrosive steel will depend on a convergence of strengthening technologies and archtectural techniques, maybe even including ones like described in the original article.
Considering all the environmental and social problems we have with modern housing and construction, this is a prime area for innovation!
https://www.architectmagazine.com/technology/two-natural-reb...
https://www.sciencedaily.com/releases/2021/01/210113090920.h...
Practical Engineering has a good video about it: https://www.youtube.com/watch?v=qL0BB2PRY7k