There are bad debts and there are good debts. Bad debts- loaning money to buy a car that won't be used for business ( Uber, Bolt). Loaning money to buy a pair of shoes, clothes, a piece of furniture etc.
There are many people around me who buy cars to transport vegetables and other goods to the market to sell, do you think this kind of loan is not productive?
Good debts - loaning money to purchase something that would appreciate in value over time. Real estate, precious metals, commodities etc.
I think when people take loans they need to think about how to generate finances on a regular basis, so that there are no problems with monthly fees with the lender. Taking out a loan to buy Real Estate, precious metals and commodities is not a small number and this kind of loan pattern cannot be done by people who do not have regular income.
They say poor people have bad debts and rich people have good debts.
Wealthy people take loans to build existing businesses and invest as you mentioned above, so there's no big problem for them with loans. Whereas poor people take loans to build a business from scratch and as a result when the business is not going well they will have big problems related to loans.
Would you classify borrowing money to invest in Bitcoin as good debt or bad debt?
Loans that are good or bad only the person himself knows, when you try to take out a loan to make an investment, the question is how do you pay off the loan debt if you have no other source of income besides investing. To me the basis for this type of loan is very poor because we all know the volatility of Bitcoin prices is very erratic.