It channels blows directly into the sternum and if the boobs on the plate are actual cups for breasts as opposed to being sculpted on the exterior, then it directs and enhances blunt blows to the chest instead of spreading the impact. If they're exterior sculpts, then they make the armor heavier and bulkier for no direct benefit. Boob plate is objectively inferior armor, and AFAIK there are zero historical examples of it.
Actual female armor looks more like what
Samantha Swords is wearing here. And for reference, It's not like Ms. Swords is flat as a board either - here she is at a con in
a Steampunk getup. You can make a triangular tent poking the 'breast' part of the plate forward a bit if you need to make room without sacrificing much structural strength, but otherwise, the armor is pretty much like male armor. Ladies would be expected to be strapping their tits down under the armor anyway.
You might be able to get away with it if the armor was meant to be almost purely ornamental, like that of several Roman emperors, but given the action pose in the first picture, I suspect she has more of a frontline role.
Sorry, fedora-Kakashi doesn't do it for me.
