Is this a trend? I'm not sure. Regardless, whenever I am on some photography themed web site, I frequently see ads for photo books. Make your own book! With your own photos! Since these companies remain in business, I suppose that having a photobook made must be a thing that people do.
In fact, I've made a few books, for one reason or another. It's kind of fun. Bit of an expensive hobby and rather time consuming to do a half decent job, but kind of fun.
And, I've seen a few photo books from other people. Not enough to really know if it's a trend, a thing people do these days, Still, there are these hints.
What do people put in these things? I've seen and made event themed books. The family reunion, the annual week-at-the-beach, whatever. Some mildly special event. Possibly even little Timmy's Birthday Party, but generally a little more distinctive and rare. I have made portfolio themed books. I've also seen year-in-review books.
If we do indeed have a new digital vernacular it certainly seems reasonable that this is what would mostly go in to these things. This is consistent with the few books I've seen.
We're printing photographs, even in this digital age. The distinction is that we're only printing some of them. We're curating, at least lightly, we're picking the best of them. We're shooting a lot of frames, we're sharing a lot of frames. We're making prints of the good ones, or the important ones. If there's only one picture of Aunt Sue, well, we have to put in in the book. Aunt Sue doesn't look very good, but she was hiding from the camera all day, so, what are you gonna do? We can't leave her out of the book.
There's a 129 pictures of the kids making goofy faces before lunch, so pick the best three of those.
Probably the goofy faces, the duckface, the iPhone-mirror-selfie, these all will look as ridiculous and dates in a few decades as the 1970s pictures of stiffly posed families in front of objects look now. We're always going to be dating ourselves. I think an argument can be made that we're getting better pictures now, in some useful sense, simply because we've got more to choose from and we are choosing them.