The built-in speaker and serial ports were merely carrying on the Apple II tradition. My design also had a bus extension port to allow additional Memory and other devices to be added, but Steve Jobs removed that feature. I did not work on the manuals or the box design myself, but I had put in place the systems and people who would do a first-rate job, and inculcated these values in Apple's management. Horn and many other people who joined Apple long after the Mac and Lisa projects were well under way never knew the genesis of many of the ideas the were later to become prominent and widely copied. For example, he attributes the internationalization of the products to the Lisa group, but it actually began when I hired Joanna Hoffmann into the Mac group partially because of her international background and my interest in providing international fonts.
Time plays tricks on memory.
By chance, I got to use a Xerox Star for the first time recently. It was in a room with a Lisa and an early Mac. The speed differences were real, but it could be that my familiarity with the Mac accounts for the feeling of clumsiness with the Star and Lisa. Of course, he might well be correct when speaking from a programmer's point of view. However, I've always been more concerned with users.