It would be useful to save a temporary local copy of a file when it is saved to the remote server in case anything goes wrong, as i had notice that i felt uneasy with the instability of our various implementations (e.g. Google Drive) when i was testing it out.
i agree, I've tried opening a 20mb ods file on a NAS, and the NAS itself is not so reliable, so many a times when saving I get errors and crashes as well.
As a workaround, I've been downloading a local copy of the file to the HDD, editing it and then manually copying it to the NAS.
So, I think a feature such as requested would help alleviate the issue.