Thank you for the detailed answer! I agree with almost everything and I have a few notes:
That’s correct, but I guess that people don’t use snippets like that is just because it’s easier to do it elsewhere without having to make your profile “full of random code” (even if it’s hidden), as you can see in the thread linked in my snippet another user posted his code on BlueprintUE instead of using the snippet section and he didn’t “waste” his time filling up forms and writing a description to make it accessible to other users (and I agree with his choice in this case)
It would be really good to be able to paste snippets inside a post without having to open another page, but I guess it’s not that easy to implement.
The same thing applies to visualization, it would be great to have the snippet preview inside the post instead of having to click a link.
I don’t know if it’s a good thing to make the default option hidden by default, it would be probably better to create a new category called “Unlisted” that is hidden by default in the User profile but is accessible from everyone from an URL (like unlisted Youtube videos).