Highlight Important Points and Memorize Them through Writing, Reciting, Listening

You need to write them down onto papers so u can memorize them easily.  

Then you can revise by reciting and rewriting them onto a new piece of paper.

Rewriting (memorize them and not looking at the book then write them onto a paper).

Then you can easily revise all the materials by the notes you created.

Why do I have to go through so much hassle for writing, reciting, and listening to the notes?

The way of revising is kinda subjective. Majority of people are visual learners; some are auditory or kinesthetic. This way is to maximize and strengthen your memory through writing (kinesthetic), reading on paper (visual) and listening (auditory). If it can help you to memorize better, why not ?