Taking loan is always risk, but if you've got stable earning to pay the interest along with the capital even if the market isn't supportive then it is not a big risk. There are people who doesn't have big spending, and they are affordable to pay the loan premium from their salary or out of the business. For them taking loan to invest on cryptocurrency will be profiting, because they've got the time which will assure with profit/growth.
Although we have a stable earning (income) doesn't mean taking a loan will be a low risk, it is a wrong mindset. We won't pay the interest of the loan only, we must pay all the amount of our debt. As crypto investment is very risky, it is always a bad idea to invest with loan money. I am sure that no one wants to spend their stable income to pay for the investment debt, right? Crypto investment must use our own money, never think to borrow money.