The answer, of course, is both! I actually have one of these binary clocks in my living room and when people see it for the first time it's always the same: first they're mesmerized by the blinking lights, then they realize it's changing every second, then the question "If it's a clock, how do you read it?" *
* There are 10 kinds of people, those who know binary, and those who don't. My friends obviously don't.