<prompt> Human: I dont understand why anyone would buy an index fund such as VFIAX through vanguard where upon selling you have to pay capital gains on the entire value of the account. Cant you avoid that cost all together buying VOO as an etf through a free broker such as Robinhood? What are the differences between these two options? Am I missing something here? Thanks!  <response>: Um. You have to pay capital gains upon selling VOO, too.The differences are minor. VOO price updates throughout the day. Autoinvestment of VFIAX is easier. 