Note that in the movie, unlike all the other artifacts, the bracelets she had on when she was sparring the other Amazons, and she even had on at age 8.
Now we know from the comics that her powers have gone through multiple revisions. The "classic" Wonder Woman that I grew up with couldn't fly, and her bracelets did nothing much other than deflect bullets. The most recent DC comics version has the powers of a god (including flight), and her bracelets are actually there to tone down her powers so she doesn't accidentally hurt everyone around her.
Given that we've seen from the movie that she can fly, and that her bracelets do more than just deflect bullets, I think its probably fair to say that they seem to be steering her more toward the modern interpretation. So its quite likely they serve to tamp down her god-like powers (as the other answer also said).
They (and by "they" I mean screenwriter Alan Heinberg, who also created the Young Avengers comic series for Marvel), were hiding those bracelets in plain sight the entire movie. It seems likely there will be a pay-off for this in the future.