You trust Google etc. to never ban your account for any reason, or to stay available 100% of the time without outages?
You trust Google etc. to never ban your account for any reason, or to stay available 100% of the time without outages?
When something goes wrong with this, you have a a fairly small chance that you can reach a human to override, but it will be an overworked underpaid contractor somewhere and your chances will be poor.
If you talk long term (decades), it is quite possible that Google falls out of favor and becomes legacy, like Myspace, with not making that much money anymore. We all know what happened to the Myspace data, they just deleted most of it at some point.
Essentially it's a lottery with your data.
Now a badly maintained hard disk is a data lottery too, but it's not clear to me the chances to retain are that much worse than Google's.
I've already had disks fail, never had an issue with Google Docs being down, and if it happens I think it will have been worth it.
I'd take "generally highly available" vs "trusting my local copy" almost all the time. And as for using something like a Git'd Excel document: most people won't do that, and Github can go down, too.
Just because Google Drive isn't perfect, doesn't mean it's not better/easier/more user friendly than what has been the standard for years.
The point is that you always need to back up. Sure, if you pay Google you can probably rely on them. But it is still best to backup anyways.