A 'selling' web design is not about flashing banners and hundreds of pop-ups. It's all about making the visitor get the feeling of freedom to make a choice.
A good web design expert makes all the sites as if they were his own, so an on-line portfolio is a nice thing to show your individual approach and personal creativity to your customers.
German web design studio made their site indeed “praktisch”. All the questions about their company’s approach, philosophy and contact info are answered by means of professional site appearance and usability.