In the future...

I would call myself a "bitcoin maximalist." The more I read about bitcoin and immerse myself in the space the more I believe in it. However, down the road I have a few worries.

I'm hoping to own about 2 bitcoin by the end of the year, and if everything goes to plan that might have the purchasing power of about 1 million dollars (of today's dollars) in ten years. If I want to buy a house with that, do I have to pay taxes on that bitcoin and then purchase the house? Hopefully ten years from now bitcoin has become universally adopted enough where the owner of the house would take bitcoin as a payment. If I send them 2 bitcoins and receive the house in exchange are there any issues with that transaction? Is it considered "selling" if I am exchanging it for something else? If this is the case, then down the shouldn't I technically have to pay taxes on bitcoin every single time I make a purchase, even with groceries? Could someone more well versed than me give me an explanation?