A large amount of investment or loan investment is very risky. When the market changes and the price drops, you must bear greater risks and economic losses.
I would say that taking out a loan is the worst idea to get started with an investment in cryptocurrency, especially for altcoins (no matter how much confident the user is). But all that said, I know at least two guys, who took out a loan to invest in cryptocurrency (many years ago) and made huge profits out of their investment. But it is entirely another topic if someone want to take a similar step at current levels. The risk factor has gone up by manytimes, and I would definitely disapprove of taking loans to invest in cryptocurrency at this point.