I can just as easily use the model class from a command line script or a desktop GUI app or something.

Quick definition clarification: if it's not in Cat, it's not a Model. It's unrelated code like any other piece of Perl. Model means it's bound to the app regardless of what is underneath. You can bind any code that provides data or services as a Model. The Adaptor stuff is precisely to do that: glue so that you don't have to duplicate external code or write code from scratch to bind it into your app.

I'll start to sound like a broken record soon. This is the summation of the issues we've discussed + a new one about testing I should have mentioned already-

• Excepting setup you will end up with 2-5 times as much code and much of it boilerplate, violating DRY and increasing the likelihood of bugs sneaking in.
• You might change FileCat to the new and improved FileCat2 at some point. With the Model you now have one line of code to edit instead of possibly dozens or even hundreds.
• This reeks of code smell-

  # APPLICATION -------------------------------------------------
  name: "OH HAI"
  default_view: "TT"
  default_model: "DBIC"
  file_directory: "some:/place/else"
  [download]

• This doesn't-

  # MODELS -------------------------------------------------------
  Model::FileCat:
    args:
      file_directory: "some:/place/else"
  [download]

• You will never conceptually separate your code from your data and your presentation. You will think exclusively in "scriptese." You will continue to give traditional, inline code preference over strict adherence to the MVC. Dogs and cats, living together.
• You cannot unit test (as flexibly) without the Model; with a Model, you can reset the Model to whatever you want via config: mock, test fixtures, etc; with hardcoded modules, you may have to resort to contortions to test things. This means you are drastically less likely to test. This means FAIL. :(

This is Perl. Do it the way you want to do it. Just like life, though, a little discipline up front, even when it seems unecessary, can repay greatly down the road in unforseen ways. I'm not the MVC cop so this is really just advice but I've been doing this almost 12 years now and Catalyst for 5 and the advice is good. :)

Google for "catalyst model" and read some of the blog posts, tutorials, and list threads. You'll get, one hopes, a deeper feel for things than from the plain Pod. The new Catalyst book ISBN 9781430223658 is also quite worth getting.