Thank you, it makes more sense now .The press conference is formed of two parts, with the second part being for written media. The stuff from this section is embargoed until a later day/time.
I guess it harks back to the days of printed press where, if TV/radio were able to tell all, then the press would have nothing new to share by the time newspapers hit the shops.
These days, written media is largely online and, again, stuff from this section of the press conference is not revealed by anyone until the following morning.