If you buy a house directly with Bitcoin, you will still need to pay taxes. You will need to report your Bitcoins to the IRS or whatever your country has, because you can't hide a house.. they will find you have a house sooner or later. So before you think about it, consider the % of Bitcoin that will go to taxes first, because maybe you don't have enough to buy it.
Thats right,it might be much better to convert your btc into fiat but it will take time since some wallets and banks were limiting the cashout. Though houses were really have tax as per law of the governmnents.