Bigger risk will always mean bigger profit, as its sole principle.
Bigger risk also means bigger losses in an unfortunate case, however, I believe it is still worth taking, especially when a person doesn't have much to loose and has only few chances to change his situation for the better. Actually, we take risks all the time, sometimes without even knowing about it. It is just more specific and literal when it comes to trading or investing.
It also depends on the responsibilities someone has. I just read again about taking out a loan to buy BTC. Honestly, if it is the year 2014, someone has little to no responsibilities, no family to feed and is at a young age and not exaggerating with the loan amount, I think it could be a risk that is worth taking. I have been reading some wild posts here in regards to financing BTC investments, like selling the wife's jewelry and stuff. But if someone decided to take out a moderate loan after crunching some numbers, knowing that if it goes wrong life would still go on quite comfortable, then why not go for it? I know people who have invested so much time into understanding BTC back at the time and if they came up with a well-considered approach to build their portfolio, loan money can be a component if someone understands the implications.