Why are some people so against summarizing and outlining?

I’m in college and this is the first time I’m really getting serious about studying. I’ve been a huge procrastinator all my life, but I’m getting tired of this and I want to change. I’m getting serious about studying and I’m looking at different techniques to help me be more effective.<br>So I’ve watched a few YouTube videos and looked at some websites on this subject. And something I see the most is outlining and summarizing. Just about everything I’ve seen says I should write a proper outline out of my notes. Make a professional outline of what I’m studying so that I can review it in a short amount of time. And yet, they also say i should summarize the details in my own words. I don’t understand this . The reason why I’m making an outline is so that I can have a quick and short review of the subject. What is the point of writing a summary in my own words? I’m spending a huge amount of time writing out all the details of a subject in my own words when I can use that time on a practice problem or an assignment that will actually get me marks. Or, I can use that time to review the material again so I can memorize it. Why do I need to reword the details in my own words? <br>I know that there are people out there who are against summarizing and outlining, but I want to hear people’s opinions on this. What are your thoughts? Is summarizing something that i should be doing in college?