Let's remember that the Note 5 is called that becasue Samsung is on their 5th iteration of it. Taking notes on the homescreen is a recent new feature. Give Apple some time. I think their Pencil is amazing considering it is their first one since the Newton.
I want to retract my original thoughts. I was thinking about it and well by the time I actually eject the S pen and wait for the screen to respond, I could have unlocked my phone and started a new note. Plus with the S pen I then have something in my hand which I have to then put away again. So really it isn't more convenient. Plus there is only so much I could write on the screen.