Well, that was a recurring pattern among the books in the '90s, crossover miniseries consisting of one book in each series with a loose unifying theme. The first one, Invasion!, had a closer connection among books, since they were all dealing with different stages of the same alien threat over the course of a century. But then we got things like Day of Honor and Section 31 where the stories were totally independent aside from dealing with parallel subject matter, and The Captain's Table where the only unifying thread was the title bar and the first-person conceit. Also Gateways, which went back to the Invasion! pattern of multiple crews dealing with different parts of the same larger threat, except that the 24th-century installments were simultaneous. The idea was to do crossovers that could work either way -- each book could work independently as part of its own series or as a standalone without needing reference to the others, but if you read them all, you'd get a larger story. (Although Gateways changed that by adding a closing volume that combined the conclusions of all the stories in a single hardcover. That got a lot of complaints.)
I guess doing 4 loosely connected short novels in just 2 volumes isn't quite the same, since the individual parts don't stand so well on their own. But I can see how it's an evolution from the existing pattern. Maybe just doing four different stories about the Badlands wasn't the best idea for such a thing. The second one, The Brave and the Bold by Keith DeCandido, had a unifying plot thread -- the search for four connected alien artifacts -- and a shared gimmick that every story involved teaming up the TV crew with the crew of a guest starship from the show and was told from the guest crew's perspective (hence the title, a nod to DC Comics' team-up series).