Thank for this nice review!
I use Google Docs for many years now and I'm happy with it.
This is a correction to my earlier comment (the version I removed now): I first misunderstood the point about the google-account for users you want to share with. I missed that the emphasis is on the risky sharing with all Internet users. Indeed: I never did, but shared a Google Sheet with a group of users of which some have no Google-account at all. I used a link and their email-adresses and think that this is secure enough for > 90% of the docs i want to share.
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