It would be ideal if ArcGIS Online could offer some type of versioning for services, etc. in an Organization's content. There have been cases where an item has been deleted accidentally. Or accidentally overwriting the service with an old gdb or even data conflicts-corruptions with the existing data because of new data additions. It would be great to restore from an older version if any of the cases mentioned leave your organization in a catastrophe.
Hopefully, credit use would not be applied to this extension. I know this would most likely use a good bit of the credited allotted storage. However, I believe some organizations who do not have the Enterprise software and their own servers to keep up with backups-snapshots, etc. would definitely be interested and willing to pay a little more to take advantage of this idea.
Also, versioning would be great for comparisons. To compare the new data with perhaps, a version that is a week old. Here you are able to run a tool or script builder to analyze the two and see where a feature may have been deleted. Administrative users (office) may not have been alerted of the recent delete (offsite) and here they have an idea of what has occurred in that week and apply any fixes in the case that the feature did not need to be deleted. The current tracing of edits for ArcGIS Online only logs what features have been modified. There is no way knowing if 'ID' 700 out of 1 million records has been deleted. The only time it would most likely be discovered is when that particular area becomes of topic and then you find it does not even exist and there are no details to help.