Sorry, I may have worded that wrong. What I mean is, if I sold 100,000 Bitcoin at $10 a coin in 2011, for a total of $1,000,000, my million dollars would have lost 25% of its purchasing power due to inflation- while the Bitcoin would be worth $2 billion.
Many have had the same idea as you, popularized by the snake oil salesman and have ended up liquidated or with their bitcoin lost or locked in broken exchanges.
At the time I doubt you could borrow against your Bitcoin, but let's assume you could.
Leaving that Bitcoin worth $1M, they would lend you a maximum of 50%, or $0.5M, but it is not convenient to borrow the maximum because at the minimum that the price oscillates a little downwards you would receive a margin call to provide more collateral or you would be liquidated. On that borrowed amount you would have to make periodic payments, which if missed, you would also be liquidated. If the exchange went bankrupt you would be left without your funds.
How much would you have borrowed to have a good margin of safety? $200K? With a downturn like the last few months, you would have received a margin call as well.
That borrow idea is fine if you are a billionaire, have like 10,000 bitcoins, and to finance your lifestyle you only need to borrow about 50 or 500 at most, but not for ordinary people as the snake oil salesman has taken it upon himself to popularize.