We consider a thinner chassis better because it makes the product more compact and portable. Thinness is a feature highlighted by many manufacturers of mobile devices, but it is essential for a wide range of products.
A burr grinder works in such a way that you can get a consistent, uniform size of grind each time, which is one of the key aspects of getting great tasting espresso. On the other hand an inferior blade grinder often leaves you with an inconsistent grind.
With a pre-infusion function you get a low pressure of water before it ramps up to around 9 bar of pressure. This gently expands the grinds to get a smooth extraction and to help prevent channeling in the cake.