Then you have answered the question of whether it's worth it. The street value of the bike is indeed that of a used bike, but if you know what components you like/need then that is of value in itself. Many people building a bike have too little background to know what choices to make. In that case it's not worth it, as you don't really learn that much that is of day-to-day use from building a bike, and it pretty much always costs more.