They are inviting you to invest in ETFs instead of mutual funds. ETFs can be more tax efficient, and if you want to time the market or day trade, you can trade ETFs during the day, not just at end of day. The disadvantage of ETFs is you need to pay a commission with each investment. At Vanguard, the amount is small, and lower expense ratios can balance this out.
Hint - savvy investors do not time the market.
