Why aren't visuals allowed for someone at the stand in court to have with them?

What the lawyer is saying is that you as a witness are not permitted to read off of your notes or reports when you give testimony. Your testimony must be from your personal memory. If you can't remember something, then you are permitted "visuals," such as your notes, to refresh your memory.

Example: When called to a crime scene, police officers will take notes and write a report. But when the officer appears in court to testify about the crime, the officer CANNOT read off of his notes and report. He must testify from memory. But if there is something he can't remember, then he is permitted to refer to his notes or report for purposes of refreshing his memory.

Either you misunderstood what the lawyer said, or you left out ALL of the relevant information.

Even if you specify the court where the case is being heard, I GUARANTEE there is not a rule that visuals can be used if the witness says they don't remember, but not if they don't.

Tragically, you think the rules of evidence everywhere in the world are the same. Not so, Megan. I'm guessing you live in New South Wales. Maybe that's the law there. You could look it up, if you care. The rules concerning evidence are often in the court rules. So googleya nsw court rules and see whatcha get.

Because it's leading. Once you show the visuals, there is no way to say you actually know what you are saying or are just basing it on the visual. Your testimony becomes completely worthless.