DNA is useful primarily for associating identities with people. Your mental data is arguably more sensitive as it contains your passwords, potentially damaging

DNA is useful primarily for associating identities with people. Your mental data is arguably more sensitive as it contains your passwords, potentially damaging or incriminating information, etc. For example, a judge can't necessarily convict you because your DNA was present at a crime scene, but he can absolutely convict you if your brain has recorded a memory of you committing that crime.