I suspect my offer of several pounds of gold will likely need to exceed competing cash offers by a significant degree to be accepted by the seller of the house I’m trying to buy.
It's not any different than having your savings in a more reliable foreign currency: you can quickly exchange it to local currency without any such premium. The same for gold or Bitcoin. Any El Salvadorian saving up for a house would be wiser to save in gold or bitcoin, than local fiat.