I'm really happy this has made it into a release! Iterating on a NixOS configuration has been crazy easy for a really, really long time. The installation procedure never matched that level of ease and fluency for new users.
I think the new installer will help more people realize how easy Nix(OS) can be (and in some ways, NixOS is easier than trying Nix any other way), and invite them to dive in without feeling like they ought to somehow prepare first. Dive in, break it, roll back, and learn as you go! I think that's a learning process a lot of people find very natural, and I'm glad that the new installer makes it more accessible to NixOS users.