Developers and designers have very different job profiles. In fact, they also have very different perspectives, i.e. different ways in which they look at the same thing.
One example: While a website designer looks at the whole external feel of a design, sets the scope for it and decides on how people connect with it, the job of a developer is very different. He or she is the one who has to make that idea work seamlessly on the inside, using code to its best advantage.
With job descriptions that are so different, there is one thing that is of extreme importance: how the idea of the “external” web design connects with the internal workings of the project in order to make it a seamless experience.
Only when developers and designers work as a team, will the end user be able to truly benefit from the application. It’s only then that they will get a product that looks great, is easy to use and is relatively error-free.