Amen to that--debt is, plain and simple, a bad thing for a person to carry on their books.  With businesses, it's another story, but if we're talking about borrowing money in order to invest in crypto, stocks, metals, whatever, I think that's a very bad idea.

I get the argument OP's economics guy made, but for one thing you have to weigh the interest rate you're paying on the loan against the inflation rate, and the other variable is how much of a return you can make with the money you borrowed--and that's a crapshoot, no matter how convinced your investment of choice is going to quadruple by the time you have to repay the lender.  If things don't go as planned, are you going to be able to pay off your debt?  I'd say there are tons of people who have far more credit card debt than they can handle, and I'd be willing to bet 99.9% of them figured they'd be able to pay it down before it got out of control.

Just don't do it.