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.
Here in the philippines, buying house with bitcoin is not yet acceptable. Hopefully in the near future, but now when you want to purchase something using BTC you have to convert and incash you Coin to be able to materialize purchasing stuff.