Well, this is only applicable to people who already have experience on investing, know what they're doing and aware of the risk associated with it. Taking a loan has an interest and if you're someone who dont have anything to lean on or dont have any assets to offer incase something went wrong with your investment then you're doomed. Rich people are making money for being knowledgeable and wise on what they do, thus taking a loan is just a basic for them to make money or to expand their business/wealth.

Thus if you're trying to copy what wealthy people do, make sure to know the consequences of your actions. Because it is still not advisable to take loan regardless on your plan for it to make more money.