I suspect the media briefings are as much an artefact of the media frenzy surrounding the case as anything else. I suspect he does them because he's asked. He doesn't say anything new really - he doesn't give much away. I don't recall him clearly stating 100% guilty. It's far more nuanced than that. Interest in the case is high, requests to hear him say the same thing is high.
As far as I can see most new stuff comes from new ordinary bystanders claiming knowledge of CB.
The only other WS case I looked at people were equally desperate for LE to charge and kept seeing lack of charge as lack of evidence. But the guy was eventually charged and, if it hasn't been for covid-19, he'd have been in court last July.
So I can't understand the issues.