Ok, this is probably a simple question, but what is the down-side to buying separate tickets for the same flights through the united website, versus just selecting a round-trip using the same flights on the united website? Quite often, there is a 10% difference in price buy buying the outbound and inbound flights separately. I'm talking the exact same flights.

There has to a reason, other than convenient clicking, why people would favor the higher priced round trip. I just don't see it. Is there something I'm missing?