When a video is paused, the video is darkened and a large pause icon is placed over it.
When a streamer is playing a game and text appears on screen, you will want to pause to have time to read it. However, the darkening and pause icon makes it very hard to read, sometimes impossible.
For an example, look at someone streaming Civilization VI. There are often dialog boxes with lots of text, which are very hard to read when the video is paused.
YouTube for example does not darken the text or put a pause icon when you pause a video, which makes text perfectly readable.