Good hardware engineers like the legendary Steve Wozniak make designs which have a minimum number of chips. They try to design a simple minimum-chip circuit, because in hardware design a minimal number of chips means to minimize the cost.
Good software engineers make code which have a minimum number of lines. They try to design a simple minimum-code program, because in software design a minimal number of lines means to minimize the complexity. Less code means less effort to understand it, less trouble while maintaining it, and less hassle in changing it.
Thus in general, less items in engineering means less cost and less complexity. A minimum number of items, whether chips or lines of code, is important to achieve simplicity and the KISS principle. The KISS principle states that most systems work best if they are kept simple rather than made complex, therefore simplicity should be a key goal in design and unnecessary complexity should be avoided.
(the image from Flickr User Fellowship of the Rich shows an Apple motherboard)