I think people are frequently trapped in some way of thinking (not sure exactly) that doesn't allow them to think of storage as anything other than Block based. They repeatedly try to reduce S3 to LBA's, or POSIX permissions (not even modern ACL type permissions), or some other comparison that falls apart quickly.
Best I've come up with is "an object is a burned CD-R." Even that falls apart though
For that matter, suppose an attacker modifies an object and replaces it with corrupt or malicious contents, and I detect it, and the previous version still exists. Can the restic client, as written, actually manage the process of restoring it? I do not want to need to patch the client as part of my recovery plan.
(Compare to Tarsnap. By all accounts, if you backup up, your data is there. But there are more than enough reports of people who are unable to usefully recover the data because the client is unbelievably slow. The restore tool needs to do what the user needs it to do in order for the backup to be genuinely useful.)