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.
Yes, it is better to avoid taking a loan for any crypto investment. The nature of crypto investment is high risks, no guarantee to get profits. Although it offers an opportunity to get a higher profit, not every time and not every coin can bring profit for us. Sometimes we may get losses because of the market situation and the price move that can change significantly. So, it is not a safe place to use loan money. Regarding borrowing money for an established business in real life, it can be acceptable as long as the business is able to earn stable profits to repay the loan money.