For the person who is good at saving, taking the loan, even for investments, is not really necessary. You could take $400 a month from pay, and put almost $5,000 per year into a ROTH IRA. That's less per month than the loan amount on the $35,000 you are borrowing. And you can only put in $5,000 per month if under 50 years old....... so, what is the advantage of investing borrowed money instead of the money you were going to use to pay back the loan. EXCELLENT QUESTION.
For investment purposes, there is only 1 advantage to investing borrowed money like the cadet loan. TIME!!! You get about 2 years of investment, without having to pay it back or save up for it. Now, will that 2 extra years of investing make a difference? This is where most people don't realize how important investing early really is:
SCENARIO: If you put $5,000 each year into your ROTH IRA, and it averaged 6% interest over a 40 year period, at age 60, you'd have $833,936.75.
If you used your pay instead, and waited 2 years until you graduate, and invest the SAME $5,000 per year into the ROTH IRA, and it averaged 6% interest over a 38 year period (Started 2 years later). At age 60, you'd have $730,408,53.
So, by using money you borrowed, at basically interest free, you gain $103,000 by investing 2 years earlier. Now; at an even more conservative 4% return averaged over 38-40 years, the difference is about $50,000.
So that is the reason for investing borrowed money. But ONLY if you can make a better interest rate than you are paying. And you will. But don't look at today's interest rates. You have to look at the average for 40 years. Remember; it might seem to suck now for investing, however when the market is down, stock shares are down, which means you are BUYING MORE SHARES for the same amount of money. Obviously, the greatest scenario is for you to buy shares every month for 39 years, and the market ALWAYS SUCKS. Then, in the last year, it goes way up and you sell off everything and put it into an annuity. But that's not reality. Reality is that it will go up and down a lot of times in 40 years. IT HAS TO. If not, we'd have hyper-inflation.
Anyway; that's why you invest borrowed money. The only other reason to take the loan, is so you have enough money to start a new life with furniture, kitchen, car, etc... This is what the loan was intended for.