A hacker attack can come in many different shapes and forms. It can be someone trying to target a certain person and get a hold of his/hers social security number, try to take loans or ordering things in their name.
But it can also be a larger attack targeting a company, either to hurt the company itself or for example get a hold of their customers e-mail addresses to then sell for commercial purposes.
Either way, it’s very difficult, not to say even impossible, to secure yourself from this kind of attacks which is why a technical solution is perfect to monitor and alert when personal information data is leaked.