I personally just copy and paste my text into the platform. I feel like if you write your articles like a story, then it will translate well onto youtube as well. So to answer your question, I use all the text in the article everytime.

My goal with anything that I do is to save time, I rather not spend my time clicking on keypoints and just have the whole text inserted into the tool. It really is a matter of preference though! Let me know what you do!