Design is about solving problems. That's the point that you have missed entirely. While I'm on it; engineers are designers too. Pick up any book about software engineering that you care to choose and the word "design" will be used extensively, especially in reference to solving problems. With regards to aesthetics, this is simple: the more elegant the solution, the easier and arguably more desirable it is to use.

And what design has to do with that? If your product does not solve a real problem it is not worth to exist with or sans design. If it does, design is important.