Most of the money in the world economy is known as “Book Money.” It exists only because an investor somewhere decided it did and invested based on that number. When a bank or investor stops thinking it’s worth that much one of the things they can do is a Write Down. The money (which never really existed anyway) ceases to exist, the banks books (and possibly their rating as a lender) are affected, the investee should become considered a bad investment, and the money is deleted from the world. But there are no other real consequences unless the investor or investee destroys enough of their wealth that they become insolvent.

You bought your house with earned money. Real money. It can’t just be erased in the same way because you played by the rules the whole time.