Can you buy a house with BTC? Yes! All you need is a buyer with coins and a seller that will accept them. The value of the transaction is as of the date of the contract, when the coins change hands.
Hmm it would be really cool if bitcoins were used as a currency to buy things.But we can't even take this possibility into consideration until bitcoins transaction speed is increased to lightning speed.If lighting network is implemented then yes people might start using it as a currency to buy things.