I don't think they are that much cheaper, specially not if you have expensive taste.
Wife and I live in one, nothing fancy and actually way bigger living quarters than what we need but it's all we could find out in the country that we liked and could afford at the time. We did not build it but the guy we bought it from did not have enough money to build an identical one from the money we paid for this one.
We could buy a very small house and barn on 3 acres for about the same price but the well was running dry and I had a bad vision about drilling a new well.