It will never be a smart decision if you take loans so you can invest. Though investing is a wise decision, but knowing you borrowed money for that, that makes it very unhealthy for an investor. However, if you have other sources to pay your debt and that they always generate an income, borrowing money may be somehow reasonable. But for a beginner who makes crypto as his first investment, then he should save for its funds first before he decide to take the risk in investing.
I agree that taking a loan to invest in cryptocurrency is very risky and carries huge risks. It makes sense to take a loan for a business that is established and brings a stable profit, and a loan is needed to scale up and increase capacity, wich will close this loan. And investment in cryptocurrency can be either unprofitable or long-term, and you need to start repaying a loan after the first month.