Also, another thing worth mentioning is that HDR makes judder more apparent because HDR accentuates silhouettes and high-frequency detail in moving objects and lights, thus makes each frame's static detail more pronounced. This has the side effect of also exposing the flaws in the framerate, making FI even more important.
People might remember old CRTs flickering more on a white background than a darker one, it's because higher peak brightness fluctuating to darkness is more obvious. And that was at 60hz. The same principle applies to when specular highlights which HDR exposes more are moving across the screen, it makes it as if each pixel is "flickering" since low framerates tend to have high frequency detail jump from one location to another. This is bad enough in SDR, but HDR makes it super obvious. Hence, FI. Of course I have no issue with people not wanting it when it was poorly implemented, but on a low setting it should smooth out panning shots at least without making it look "too smooth". I always put it on max. Once you get used to it it becomes hard to go to the movies and watch films without it. It's like Plato's Cave or Alice taking the Red Pill, leaving illusions behind.
There were several space and landscape panning scenes in Rogue One, Interstellar, and of course the latest Star Trek which were just brutal to watch in the theater, but once I got home I could experience those movies in a better way without that annoying judder and skipping. Motion blur is also annoying too. A lot of the benefit of 4K static resolution gets wasted the second things are in motion, due to blur. But frame interpolation allows you to take more full advantage of the static resolution. Temporal and spatial resolution go hand in hand, and help (or hinder) one another, so higher framerates via FI add up to a much more convincing and immersive experience. Clearer, sharper, more fluid. Just better in every way.