In fact, it would probably kill you.
Yup, apparently the boob armor we're used to seeing is literally the opposite of what you would want in a serious battle. Not only is it historically inaccurate, it's highly likely that it would kill the person wearing it. It's the opposite of practical. It's just there to be sexy.
"Let’s begin by stating the simple purpose of plate armor—to deflect blows from weaponry. Assuming that you are avoiding the blow of a sword, your armor should be designed so that the blade glances off your body, away from your chest. If your armor is breast-shaped, you are in fact increasing the likelihood that a blade blow will slide inward, toward the center of your chest, the very place you are trying to keep safe. But that’s not all! Let’s say you even fall onto your boob-conscious armor. The divet separating each breast will dig into your chest, doing you injury. It might even break your breastbone. With a strong enough blow to the chest, it could fracture your sternum entirely, destroying your heart and lungs, instantly killing you. It is literally a death trap—you are wearing armor that acts as a perpetual spear directed at some of your most vulnerable body parts. It’s just not smart."
Let me say that a little louder.
We all know what Tony Stark is adding to his next suit upgrade, am I right?