Notes are not pointless, they enable you to understand your prescribed texts to a greater extent, and allow you to gain relevant ideas which can form the basis of your essays. Notes therefore constitute an important component and therefore make a positive contribution towards your HSC exam preparations.
I personally memorised my analyses and incorporated them into my essay responses while ensuring I would adapt them to the specific questions. This approach allowed me to receive an 85 as my Examination Mark in English Standard. if you are taking a higher level of English and/or aim for a high mark (i.e. band 6/E4), a more thorough approach will be required. You should use your notes to gain a thorough understanding of your prescribed texts and familiarise yourself with quotes and techniques used within each text that you might be able to include within your essays. This should be supplemented by relevant practice, meaning that you should attempt to complete module-specific questions that specifically target your prescribed texts, and subsequently identify areas of improvement by seeking feedback from your teacher (if possible).
I hope this helps!