Sincere question: why is this better than going with the vast array of mutual funds and ETFs available? Is it the return rate? Something else?

It seems like your typical ETF or mutual fund is easier to get into and get out of, just a few clicks on your brokerage of choice.

Your answer brought up the obvious general answer: the only way to make passive income from investments is to already have a lot of money. To me there's a point where the method of investment almost seems like an irrelevant detail.