I thought about that but it isn’t as simple as it sounds. A lot of banks hold custody of the bitcoin. If something happens to the bank, country, or house they can sell your bitcoin because you don’t hold the keys when you take out the loan. Also, the interest rate is over 16% on the websites I’ve looked at so you are paying about the same as capital gains tax. And you have to post a significant amount as collateral. If the bitcoin price tanks, then you have to post more collateral or get liquidated.