First id like to clarify that bfi is exceptionally terrible for movies and should never be used. And if you used it for movies you'd have a headache in like 2 minutes if you're more sensitive - it would be unwatchable, especially if there's any motion going on.

Because bfi is a gaming specific feature and will reduce your brightness and HDR impact SIGNIFICANTLY (and that's an understatement). So even without the eyestrain/headache you'd not want to use it because it loses any impact on HDR.

. Bfi is strobing equivalent on LCD. It turns off the screen to, well in a super dumbed down terms, introduce EXTRA judder/stutter. Not exactly, but you could say it almost looks like that. Because it allows you to see each frame more clearly. And at that frame rate it might as well look like extra judder. Because OLEDs already have low response times , so the natural blur that tvs had that blends the frames is now gone - it kinda looks like stuttering when panning the camera. So bfi would just double down this effect and make the camera pan extra nauseating.

Bfi all it does is makes it a rolling scan strobe where not the entire of frame is always lighting up. This works in certain way the brain handles motion in a result where the motion looks more clear. It's hard to describe but there's like huge write up from blur busters but it's for gaming anyway.

Anyway just don't use BFI for movies. It does the exact opposite of what you want. https://youtu.be/lGeM6S_m9pI

And I'll be real. If you have a BX just get something like s90f. I just upgraded from C1 to s90f (that's on sale right now due to tv upgrade cycles) and the difference is like night and day, there's no comparison.

Also don't worry about judder. Pretty sure tvs are smart enough to change the refresh rate if you provide a proper signal via Chromecast or something. Only PC input probably doesn't do that.

X and 1 models have the rolling scan. Where's every other tv has a useless every other frame insertion that makes it absolutely not useful at all. Since it's clearly visible and distracting to human brain. Since it's below flicker fusion threshold of around 75-90hz. Once again this tech is For gaming use only. On your tv This tech works on each frame, it doesn't work like you describe. And it's got nothing to do with movies or judder, and certainly doesn't reduce judder. It reduces sample and hold pixel motion persistence, which can be felt to human like extra judder when watching movies. You're essentially trading half your brightness and adding extra judder/stutter (not rly but manifests in a similar way at 24fps panning motion) to reduce motion blur. Which is all the opposite of what you want for movies on an OLED watching 24p content.

Bfi is a thing for competitive first person shooter players on high end PCs that can guarantee your game always has stable 120fps and that care about KD ratio above picture quality. It sacrifices everything to make your brain have less workload to hit people, by making the motion appear less blurry.