She comes back for a specific reason, not only to see her parents and meet everybody on the team, which you saw all throughout the season — there’s four specific times that she came back, and you’re gonna learn about why she chose those four times and how they’re gonna play into not only the mistake that she made, but the consequences for somebody like her, a speedster traveling from the future to the past, and what that means for Barry and the team.
Barry certainly learned his lesson about time travel and the effects that it can have.