I think it's one thing to put your money on something being successful in the future, and putting money you loaned onto something. Sure, you may end up as the winner, but you may just as well end up on the streets, like... literally.
I personally have never taken any loan because I hate the idea of being indebted. I have always maintained my personal emergency reserves so instead of loaning money I take it from my own reserves. That's why it's a bit hypocritical of me to suggest loaning. However, let every man decide for himself. If a man is destined to be poor then even the best advice in the world won't make him rich. If a man is destined to become rich, then taking risks is the fastest way to success. That so called destiny is nothing final, since it changes as you change yourself. To make a good investment you must first become the kind of guy who does good investments naturally. I believe the particular person who I encouraged to take a loan is on his way to become that kind of guy. He's reading the right books and he is thinking the right thoughts.
The right circumstances are important too. Remember how Soros "broke the bank of england" for $1 bil in 1992.
It was one of the most famous trades, albeit highly leveraged.
They could have just turn the tables on him as they did with Hunt brothers silver "corner", but they let it slip this one time.
Being in bitcoin is risky enough for me, i don't need to take loans to double up on this risk.