Here's the fear I have with "self-taught" people. How much do you really know?
Making a website work or look good, or both, is not enough. How well is it coded? Do you know best practices, not only for performance, but for security? My employer hired a relatively well respected company to build a web based application that would house medical data. It was my job to put a server in place for them (RHEL) and more or less make sure that their code would run on it.
Well, they used PHP, and since I know PHP quite well, I thought I'd check how they did a few things. I was horrified when I reviewed some code and saw basically:
$sql = "INSERT INTO table_name (col1,col2,col3) VALUES(" . $_POST['blah'].....
Now, formal education does not mean you're going to learn these types of things, but what it does tell me is that you can learn in a formal environment, and if need be, I can put you in training and expect you to absorb the material in a meaningful way.