Bitcoin like a stuff then worth as money, is any item or verifiable record that is generally accepted as payment for goods and services and repayment of debts in a particular country or socio-economic context, or is easily converted to such a form. The main functions of money are distinguished as: a medium of exchange; a unit of account; a store of value; and, sometimes, a standard of deferred payment. Any item or verifiable record that fulfills these functions can be considered as money. So there free you for anythings. Wanna buy house? more stuff? there back again how you do better yours self and family.
From the beginning I know bitcoin as online currency that has high price from time to time. Of course you can buy a house using bitcoin as payment (if accepted) or simple convert it into fiat money to pay for the house. I'll do the same if bitcoin goes up very high, that's why it called as long term investment.
The real essence of the question is not really using your bitcoin to buy a house, it just stated that if our investment will grow do we buy a house, and the simple answer for me is yes, why not? That is money that we earn from our hard work so we should also reward ourselves on that.
Maybe he doesnt know what OP really meant in his question. No one would surely say no to buy a house which almost of us had a dream on having our own house. If we are making profits with bitcoin in the future and could able to buy a house. Then why not.?