Self-directed IRAs let you invest 401(k) and traditional IRA money in real estate, private equity, and private lending instead of stocks and bonds. You control the investments and keep all returns, but they're not guaranteed and depend entirely on your choices.
If you have a 401k or traditional IRA and you don't want all of your money invested in the traditional financial markets, and you feel you can make a better rate of return investing in real estate, private equity, private placement deals, private money lending, private credit funds, whatever you want to invest, if you think you can make a better rate of return, then you might want to consider the self directed IRA option. Now, like I said, I can't advise and tell someone that just by opening a self directed IRA you're going to make a better rate of return. Ultimately, the rate of return is going to be dictated by you as the investor. And that's really what's so powerful here, is that you get to take control and ultimately chart your own destiny and you're not beholden or reliant upon the traditional financial markets.