The lack of needing an account is a (or the) key feature: one I wish more online services copied. How much better and more frictionless would the web be if we weren’t having to log into an account everywhere we went?
How do I get back to my docs from a second device?
If each doc has a unique URL, then bookmarks? Most browsers already do this. I’d be willing to argue that browsers should make sharing bookmarks from one device to the other easier and account-less, too, but that’s a different rant.
Bookmarks might be fine for technical users, but these days I do not see non-technical users use this feature at all.
Not really. Regular users send links to themselves all the time as a way to bookmark things.