Just to awnser the question why not using windows. Here are some ideas why the author might have used nix instead:

- reproducible (with minor adjustments even on non-WSL systems)

- if you are used to nix, there is not much which beats it in terms of stability, maintainability, upgradability, and fun (?)

- additional services are typically easier to set up like tailscale-acl, used by the author, which uses pulumi under the hood

- despite some downsides (disc speed was an issue when I used it), WSL is surprisingly capable