Can you help me understand why devenv is needed instead of a shell like this/what is gained?

    { pkgs }:
    
    pkgs.mkShell {
      nativeBuildInputs = with pkgs; [
        # build tools
        cmake
        ninja
        gnumake
        pkg-config
      ];
    
      buildInputs = with pkgs; [
        # java
        jdk8
    
        # compilers
        gcc
        clang
        llvmPackages.libcxx
    
        # libraries
        capstone
        icu
        openssl_3
        libusb1
        libftdi
        zlib
    
        # scripting
        (python3.withPackages (ps: with ps; [
          requests
          pyelftools
        ]))
      ];
    
      # capstone headers are in include/capstone/ but blutter expects include/
      shellHook = ''
        export CPATH="${pkgs.capstone}/include/capstone:$CPATH"
        export CPLUS_INCLUDE_PATH="${pkgs.capstone}/include/capstone:$CPLUS_INCLUDE_PATH"
      '';
    }