Odd advertising

TCM promote their upcoming movies by showing theatrical trailers. If you've been watching TCM recently, you've probably seen that Love Affair, the 1939 romance starring Charles Boyer and Irene Dunne, is coming up tonight at 8:00 PM ET.

However, there's somethinf wrong with that trailer. It's made of entirely of publicity stills, with a voice-over. I honestly can't recall seeing a trailer like that before. I could imagine something like this being made for a re-release, since the studio wouldn't put so much energy into editing a promo for an older movie. But, the blurb at the end calls it an RKO picture, with no evidence that this is a re-release. (If you watch other trailers carefully, you'll note that some of them state that the movie is a re-release.) Also, I can't imagine such drivel as we hear in the voice-over actually convincing the moviegoers of 1939; it sounds more like something that would have been used on TV. So what prompted making an odd trailer like this?