That’s not a fair statement at all. A writer isn’t a computer expert, and shouldn’t have to be. Google Docs specifically positions itself as a product that takes care of all the data handling for you, and they market that fact quite heavily.
On the face of it, I can definitely see the upside: "the cloud" is typically synonymized with safety ("your data is backed up on our secure servers", etc.), not to mention the fact that you can edit your data from any of your devices logged into Google. Heck, you don't even need to install Office anymore: you just go to https://docs.google.com and it's all there.
I do agree with you, though: one of the most important rules for computing in general is to keep multiple backups of everything. A while back, a friend of mine made a habit of emailing herself drafts of her work, and kept multiple copies on her computer. It did save her once or twice.
Out of the interest of brevity, I didn't want to go into my full setup. However:
1. I write locally and have both manual and automatic backups (local and remote)
2. I upload drafts online for beta and alpha readers to leave comments
3. My group used to use Google Docs for this but stopped once I discovered the data loss
Happily, because local is the source of truth, I didn't lose any of my writing. I did, however, lose some feedback, and reconciling things was a pain.