World war 2: Germany invaded Poland and was preparing to invade France. To !circumvent the france defense they attack from belgium, since the defense is weaker there. They implement the same massmurder system they implemented in Nazigermany. Luckily the Dutch already collected the data they needed, so they could start the massmurder more easily. That is why we need to take care about our data.
First of all, we don't really care, do we?
Second, it's not just identify and authenticity.
There are data breaches that leak a lot more information than just an identity. Sometimes the mere fact that your identity is in a breach is problematic already.