Would you classify borrowing money to invest in Bitcoin as good debt or bad debt?
Depends on the interest rate of your bank. If it's two digits, on the upper side (20-30-40 percent), then it doesn't worth the risk to my mind but if it's a low percent and you have a salary enough to pay your loan and you won't ruin your life doing so, then why not? He who does not risk will never drink champagne, you know.
By the way, if someone takes a loan to buy bitcoin when it reaches its ATH, I would call it a bad debt but if someone buys for example before halving or soon after halving or after the crash of its ATH, then I would call it a good debt.
It does not depend on the bank's interest rate, it all depends on your ability. If you have a job and can repay the loan even if your investment fails, an investment loan may be considered. Borrowing money for investment or business is not recommended, but if we have a plan for it and can pay off the debt, we can try because there is no success without trade-offs, I agree with your argument. But we need to know how much our ability is, don't be too greedy or too subjective, otherwise, we will have to pay dearly.