I am as old as Gandalf in cse prep years and I have something to add.
Back in those good old days, I started off by making notes online. NCERT, eco survey, budget, newspaper, things I got wrong in prelims test series, anything you name I have made notes online. I have even made notes on niche topics like urbanisation, social empowerment etc also online. What happened as I have only now realised was that there was no connection between me and the notes that I made. Just like how ecom companies have alienated us from our local sellers I have alienated myself from my work. I could not feel it.
You know that feeling one gets when one comes across a question and vaguely remembers seeing it in his notes because of some peculiarity like he may have corrected a spelling mistake or may have underlined it, I never got it. My mind's eye was blank. Add to these the fact that the internet was and is a rabbit hole, my efficiency was always very low. I could not also sense the scale of material I have been accumulating.
Anyway, now I have nuked most of my online notes and started with pen and paper note making sitting away from the internet. I am getting printouts of most monthly news compilations instead of underlining them online. It feels good for now and the coming days will judge if I made the right decision.
I advise newbies to experiment soon with different media and stick with whatever is comfortable. Veterans can try pen and paper notemaking if they have wasted enough time online like me.