Yeah, the reason driver/navigator works better is that both are engaged and focused.
Otherwise it’s very easy to get distracted (or doing something in parallel which is why I am not a fan of shared editing). Then it turns into something more similar to sitting next to each other rather than working together.
The most important aspect is that the person with the keyboard shouldn’t take any decisions/actions without first talking to the other(s) or you risk them disengaging.