Mansion in my country with current price need at least 2 Bitcoin. Because in town a normal house can cost 1 coin and it is right depends on what country and location of the house. My house if price now need 0.3 BTC at current price, maybe if price can increased x2-x3 from now, people who hold 0.1 BTC can buy house in village because still cheap.
To me what's funny about this whole debate, and specifically the OP's idea of the Mansion is that he doesn't mention maintenance. Even if that amount gives you enough to buy a mansion, on an average salary it doesn't give you anywhere near enough to maintain it, meaning you're going to have to sell it, and probably for a lower price than you bought it for. You wouldn't be the first person to win the lottery and that happens to you.
More generally, that amount will hopefully have a much higher purchasing power in the following cycles, but the worst thing you can do is to spend it on a fancy thing, better to spend small parts, that way you don't eat your net worth and you can enjoy the profits.