- it's an unexpected mental context switch - if I'm concentrating on anything else, it takes a moment to switch to interpreting directions, sometimes enough to miss information
- if the traffic is not smooth, the distance becomes harder to judge - the turn is in 2km, but I did two stops, so how far is it now?
- "third left" becomes vague if you've passed a left while the message is played - was that included or not?
Constant information you can reference at any point is so much better for me. (Although a "tell me the directions again right now" button would solve some of them too)