Why do you suppose grand juries operate in some states and not others?Should grand juries be the sole charging mechanism of choice across the country?

Why do you suppose grand juries operate in some states and not others?Should grand juries be the sole charging mechanism of choice across the country? Make an argument supporting your position,

Make sure your answers reflect knowledge of the material in Chapter 11.

These are the professor’s notes

The textbook is Criminal Procedure (Justice Series) (Subscription) by John L. Worall. 3rd edition.