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.
Yes, you can buy bitcoin by earning bitcoin or investing in bitcoin. If you are earning bitcoin and you want to buy a house , you must be a full time here in bitcoin forum also in your job to this forum. And if you are investing in bitcoin make sure that you invest a huge amount of money so that when bitcoin pumps, you will gain a huge profit and you can buy a house now because of bitcoin.