if CDPR decided to secretly release of big update with no marketing at all, they had to have economical reason or reasonable strategy for that, not a Christmas suprise. That is why I am loudly thinking about real possible reasons behind it
Well, the explanation is clearly a pretty fairy tale.
Focusing only on the issue of lack of publicity, possibly due to lack of content in time.
The first thing is to think about the base marketing or "payment", the company would not have problems in that.
Then we go to the part that is currently trending in the card games that is the revelations of the community, that is clearly much more efficient than throwing a ninja update only 24 hours before the established date, is that if you were surprised you did not have too much Time to get excited.
In this last section we have a content issue, they must have the cards so that people can show them, what I think is that they simply did not have them all until the delivery date was advanced, so it was difficult to make an efficient revelation routine.
Recall that previous expansions came out with "coming soon" in some aspects and with certain cards with a very low quality compared to their standard for the game. Both things were overcome in this latest version, which may not mean that they did not take until the last day available to polish the details.
Without any of the normal forms of promotion something had to be done and they advanced it 24 hours (Not to mention the negative of the coincidence in days of updating with HS).
Of course, their version may be true, who knows, perhaps they genuinely came up with the idea that the worst way to promote an expansion was a good thing(At this point I don't think it's important, just to digress a little
).