Dhall was inspired by Nix, and created by a longtime Nixer.
Also as someone who likes simple FP but is not some sophisticated typelevel programmer, Dhall looks really complicated and verbose. To me, the Nickel approach, where authors of libraries in the language (equivalent to things like nixpkgs.lib) can pepper their functions with type annotations, but users can use what looks and feels like a simple configuration language, seems like a better approach for the domain.
I can't imagine getting all of the PHP developers I support comfortable editing the equivalent of shell.nix in Dhall themselves. Nix files I can ask them to edit without taking up too much of their time or focus.
Also as someone who likes simple FP but is not some sophisticated typelevel programmer, Dhall looks really complicated and verbose. To me, the Nickel approach, where authors of libraries in the language (equivalent to things like nixpkgs.lib) can pepper their functions with type annotations, but users can use what looks and feels like a simple configuration language, seems like a better approach for the domain.
I can't imagine getting all of the PHP developers I support comfortable editing the equivalent of shell.nix in Dhall themselves. Nix files I can ask them to edit without taking up too much of their time or focus.