Reading with HD is different than reading with nomod. It will not help you at all. Learn nomod first, then move to HD.
"Overall, I think people tend to reveal their true selves when they step into an avatar. As I said earlier, they probably feel some sense of freedom. But freedom easily gained quickly turns into a false sense of omnipotence."
Shat it does is help your timing. It makes it so that you cannot rely on the hitcircles to tell when to click the note, instead you have to listen to the music to determine when to do so. I would recommend using HD is your aim is already decent. If you can't aim, you won't get anything out of HD
Tell me Wheein isn't gorgeous and see what happens
HD varies with who uses it, since the person who uses it tend to like different kinds of AR(ex. 8,9) or they simply find it better with hidden on than none,in my case,it's because I'm annoyed with approach circles and I seem to aim better with hidden,for early players,it may be easier for you to start HD at hard mode,as the notes there aren't that confusing and you can go with the flow easily.