I think we should say that good debts are assets while bad debts are liabilities, and Bitcoin on the other hand could be referred as a good debt, because of its potential to rise or fall in value depending on the current nature of the market, and how long the period of investment. But however, I'm not a type who will advise people to take loan so to invest in Bitcoin, because just as the interest of your loan keeps accumulating, Bitcoin is an investment nobody is sure of it's next moved, as it is been controlled by market demand & supply. And don't be surprised that the due day you were supposed to pay back your loan, Bitcoin could be 20% lower or higher in price, depending on the nature of the market at that very moment.
An asset will also not always be good debt, even if it is capable of making a profit, but this income is not enough to even cover the payments on this debt, then such an asset will definitely be just as bad. As for buying bitcoin with credit money, this is probably the worst idea that could be accepted, because I don’t know a single story when someone took a loan to buy bitcoin and didn’t lose money on it, let alone to earn something.