401(k)s usually have limited investment options, you'll have to check if these funds will be available under your company's plan. To answer your question, why

401(k)s usually have limited investment options, you'll have to check if these funds will be available under your company's plan. To answer your question, why on Earth would it be a terrible idea? They are two index funds - total market index and international index. Investing in low cost index funds is generally considered the best way to invest for the average person. Furthermore, with 401(k)s you can freely trade without having to worry about triggering capital gains taxes, so there's no reason not to move the entirety of your investments in these asset classes fully over to the new funds in a 401(k).