Buddhism is a hundred times as realistic as Christianity it is part of its living heritage that it is able to face problems objectively and coolly; it is the product of long centuries of philosophical speculation.
Americans are interested because they are open-minded. They have an education system that teaches them to find out for themselves why things are the way they are. Open-minded people tend to be interested in Buddhism because Buddha urged people to investigate things - he didn't just command them to believe.
To observe and watch one's own mind is something really interesting. The untrained mind will run and follow its old habit patterns. Because it has not been trained and taught, it will get lost in all kinds of stories and issues. Therefore we have to train our mind. The meditation practice in Buddhism is all about training one's own mind.
According to Buddhism, individuals are masters of their own destiny. And all living beings are believed to possess the nature of the Primordial Buddha Samantabhadra, the potential or seed of enlightenment, within them. So our future is in our own hands. What greater free will do we need?