WolfyAmbassador
I just wanted to clarify some things. Films and such are 24fps. Sometimes 25. TV is 30. Now, if you double the frame rate of TV, you get 60. So with a 60hz max refresh rate, you can frame double the tv without issues, since you just duplicate frames (you can do interpolation if you wish). Now, look at film. 24*2 = 48. So you would double it, but you fall short of the max. And what do you do with the extra 200ms? Well, you need 12 more frames. You can take some frames and double them again, but then you introduce a kind of jerkyness to it, all in an attempt to reach 60fps.
So, what about if you want to have 120fps. Let's look at that. To bump up 24fps to 120, you multiply by 5. So, you can make four copies of each frame, and you have 120. What about 30? You just need 3 copies. (30x4). So it works out better with more smoothness just due to the math involved.
So, how can you get 24fps to 60fps looking smooth? I suppose one way is to crank it up to 120fps and then halve the fps. It's simple, isn't it? But it requires more processing power... however, since this is running on the computer this is not an issue.
I hope I've explained it well enough for you why TVs have smoothing at 120hz and less so at 60. Some of them 60hz tvs do have interpolation, just look at this tv...