Jury's out on the safety issue. It's definitely safer on tarmac rallies, but on dirt/gravel the road conditions change much more. Pacenotes can encourage you to charge 10/10ths into a blind corner only to find mud or loose gravel. I guess if you have a car prerun for you in the morning you can figure that stuff out, but we're still very low budget compared to the WRC.
Even without pacenotes, you'll have important or dangerous turns indicated in a route book, so the co-driver keeps track of that. But, like I said, without pacenotes there's a lot less to do.