YouTube videos play in either 30 or 60fps locked. If you upload a screen capture recording at either of those two frame rates, things will look smooth. If you upload game footage with a variable frame rate, or use software that records at a locked frame rate independent of the game, then the resulting video would have a bit more stutter. I.e. A game played at 30fps would look better than the same game played at 45fps even though the 45fps would be smooth to the player at the time. That’s because the video would have frame skips/doubling ever so often due to the odd number of frames.
If you watch any bigger named YouTube gaming benchmark channels, you may have seen the reviewer mention in their videos not to pay attention to how the gameplay recording looks, but to pay attention to the frame time graph they display. The above explanation is why.