Look at the impact phones and instantly accessible information have already had on peoples brains, attention span, and critical thinking skills. It's a microcosim for the problems of outsourcing memory and thinking to non-biological means. Even if stored locally in the body it would be a distinct storage medium would inherently be separate from the self in a way our own brains are not and that's not even considering bias in the databases used in conjunction with diminished critical thinking.
Imagine you had a great encyclopedia with infinite pages. Any question you desired to know you could query the book, even language poses no barrier. You simply reach out your hand, point your finger, and it WILL appear with precisely what you desire presented right before you. Certainly such a book would contain great knowledge, you may even call it a book of wisdom, but you could never call the book itself wise. Now remember, it's not that the book can appear but it WILL for any question from the moment of birth. Now consider too, with all that knowledge, what if it also sometimes contained lies? Could one without wisdom ever discern the truth from lies? You will have infinite information and yet know nothing. This sort of technology will be no ones salvation, it will be their doom. An eternal damnation for there will not even be any self left to die.