As others have mentioned, Puccini was dissatisfied with the plot of "La Rondine", and revised it several times. Here we have the third version of 1921, which includes at least 30 minutes of different or heavily re-arranged music. There is, for instance, an entirely new scene with three clothing sellers, and the character Rambaldo reappears briefly in the third act. However, musically, I don't feel that the result holds together any better than the third act of the original version, and the plot is certainly no more convincing, and seems even a bit more contrived (if this is possible!).
I am glad that this performance was recorded, since I have long wondered what the 1921 version might sound like, but I'd just assume listen to the soundtrack without watching the video, since I found the frequent dancing a distraction, often inappropriate, and occasionally embarrassing. The scene of the third act includes a picture of a human corpse (the fallen swallow, I guess), and a large birdcage into which our dear Magda must eventually retreat. I think this speaks for itself in terms of production values.
For the most part, the musicians do a good job; just turn off the picture and listen!