Yes I know that. The issue around just using one VM is that it is single point of failure IMO. Yes, is unlikely that VM will die, and yes, the VM image itself is likely backed by reliable storage (they are supposed to be disposable IIRC, you'd ideally want to attach some kind of volume which is extra $$$ -- correct me if I'm wrong here).

That said, my point was with little extra money -- features such as easy sharing, security, versioning, nice mobile apps, and time saved moving around things manually (like photos), offline access (and if you use rsync cron, not worrying about conflicts) etc makes it worth that extra few $$$.

I'm a linux user but unfamiliar with how to set up and arrange those technologies in reliable (for my taste) fashion.

The comment your responding to is actually a toungue-in-cheek reference to the original Dropbox announcement on Hacker News: https://news.ycombinator.com/item?id=8863

It's not to be taken seriously.