What's the point in a 120Hz TV if the signal source is 30 fps?

Question

TVs

I read a lot of articles on this topic and it still remained unsolved.
Games are discarded immediately. We're talking about TV.
I watch the air a little, but still - what is his FPS now?
The main issue in films, they are all encoded at 30FPS, 60FPS content is starting to come across little by little. And all already old TVs are just 60 (50) Hz. So why update the picture on the screen if nothing has changed in the signal picture during this time?
For a long time I looked in the store at 2 identical Sony TVs from neighboring series, 50 and 100 hertz, stood next to one another - I did not see any difference in any scenes.

Answer 1

1. Games (do not discard - this is also a source of content)
2. Ether yes - so far nothing.
3. There are already a lot of films at 60 Hz
4. Extrapolation, or whatever it is - a smart TV set, slightly throws frames. Looks unnatural, but cool.
And yes, marketing, IMHO