I do what you describe for nonfiction (blog posts, mostly) but even there I’m likely to give it a look in a different format before posting. For fiction, rather than print to paper, I’ll print to pdf and mark it up in a pdf editor (my favourite is Noteshelf on iOS). Then I can put the marked-up pdf in a window next to Scrivener (or even import it to Scrivener! Live dangerously!) and make my edits. Paper shuffling and ink cartridge use neatly avoided.
I use the paper when an idea comes to my mind to not lose it, since I do not always have the computer
Cheap 80-page composition books (when they’re on sale, I buy a few. Last purchase was 50 cents each) and medium-point ballpoint pens. I use them a lot for writing down ideas, and sometimes whole chunks of story just fall out of my brain onto the pages. Then I type them into Scrivener later.
I use Drafts 4 for that, because I always have my Apple Watch with me and usually my iPhone. Then I simply send the text to the Scratch Pad. Simple and quick.
I almost never have paper and pen available when I get ideas, so I used to have to search for it first and when they were found the idea was usually lost.
And for editing, exporting to pdf and reading on my iPad is more efficient than doing it on paper because when I make several notes and change my mind I can simply erase on the iPad and try again. Or move what I scribbled in the margin to somewhere else.
“Premature optimisation” - I’ve witnessed this phenomenon a lot, but could never put a name on it. Sounds about right!
When idea pops my mind I absolutely have to write it down somewhere. So learning from these “situations” I’m carrying with me always note book and pen when I’m out. I have post it stickers all over my apartment so I don’t have to run to find paper if my computer isn’t on. Lately I have been using my phone to writing if I’m traveling on like bus, this because there has been couple times that I could not understand my own handwriting 
I like to keep a small notebook with whatever comes to mind, in no particular order. Sometimes I’ll go through it, take out whatever looks like a workable idea, and put it into my “Project Scraps” file in Scrivener, where everything goes until I accumulate enough to split off into its own project.
Then I’ll have a composition book dedicated to one project where I’ll still jump all over the place but try to fill at least one page on any one scene or subject. Usually when it’s about half full, I’m ready for a dedicated Scrivener project where I’ll organize everything, start filling in gaps.
I carry a notebook and pen around with me at all times in case an idea comes to mind when I’m away from my keyboard. In general, I prefer my computer as my typing speed is faster.
I used to write on paper a lot. I found it very relaxing, like meditation.
However, I did notice after a long time of writing and settling into my style and voice, that the pace sped up on paper and detail was lost to a point it didn’t sound like the style and voice I wanted. I couldn’t get the thoughts down fast enough, so everything ended up abbreviated, or I simply ended up skipping thoughts. So now, I mostly use paper only when I need to plan, or brainstorm, or just plain scribble.
handwriting in Scrivener software works fantastically IF you have a device made for it. I have a laptop and a XP-Pen star G430S art tablet that has a built-in stylus, amazing control, like drawing on paper.