I think it is an issue to be concerned about, since now, according to Dave, there are ghost categories. If I understand him, whatever categories our books currently are in now may lead nowhere, so we must change everything. Yikes.

Look at what Amazon has done to the sales page, too. It now allows you to examine the book cover at very large size--which is of no practical use to anyone buying a book. What are they thinking? You'd want to examine some other kind of product in that nearly microscopic detail, but not a book cover.

Amazon seems to have made some changes to their category selection process. (I apologize if this has already been discussed here.)

The Kindlepreneur guy, Dave Chesson, sent out a long email through his mailing list talking about how some are actually 'ghost' categories.

This is it. https://kindlepreneur.com/how-to-choose-the-best-kindle-ebook-kdp-category/

Some categories seem to overlap, and are apparently the same category with different names. I skimmed and honestly wasn't able to make much sense of whether this was going to affect me or not. But KDP now suggests that I update my categories when I went to edit something else. My book is not selling right now anyway so it won't make much practical difference, but its always nice to understand what I'm doing when I change something. Is this an issue to be concerned about?

How long before Amazon sells us ad-space on Prime Video?

"Pay a set amount for a 30-second ad spot; promote your new thriller novel during this week's new episode of Reacher."

I could see it.

Oh! I'll have to look again. I saw the second dropdown, but I didn't see urban or paranormal.

Or maybe they were added after I created the book. I thought I had looked very carefully at all of the possibilities offered.

I'd worry about the possibility of Google parsing your entire book for its AI schemes more so than worrying about a third party scraping GooglePlay for the first 20% of books to try to train their AI.