This claim has often been made, but I think it's that you're unable to speak truth to power and have frank discussions when you're doing it in secret, because then the government can always deny what has been recommended from the public service and there's no record of it, so the public service can't speak up and say, “No, that's not what we recommended.” Openness facilitates having frank discussions.
If there's a duty to document, then it will be illegal to go off-line, so hopefully penalties for doing that, among other violations in the duty to document, would make it very clear that if there is a decision made and there's no documentation of it, obviously someone's violating the law.
That's the way to go forward to have good democratic and good government decision-making, as opposed to the secretive and bad government decision-making we often see now.