This question is really unclear. So I will answer this one in two way, is this one house? If so, then NO, it is not. If this is more than one house, multiple houses, that will benefit people then yes. I think that we need more housing that is affordable available to people.
In a world plagued by poverty and low wages, it is ridiculous to even consider building something which would cost $100 million. Someone with that kind of money has lost sight of reality. Who truly needs a home that would cost that much is unclear when most people survive on a home of a modest size.
No, it is not necessary to create housing that costs more than $100 million, because people can live safely and comfortably in housing that costs much less. At the point of $100 million, the buyer just wants luxury, rather than the necessity of a safe and healthy shelter. But if a person can afford it, I don't care if they want a $100 million home.
The world has a finite amount of resources that should not be exploited for a few people to live opulently. I believe that wealth can be used and even flaunted without spending a million dollars on a house. In the past it could be said that the rich worked hard to get where they are, but often the little people are exploited and stepped on to make it happen.