I see a lot of people using Rclone for restic. What advantages does it provide over using cloud storage providers like S3 or GCS directly with restic?

Otherwise this looks like an awesome project!

One of the advantages is to be able to put the destination as 'append only', reducing the risk in case an attacker gained access to the backed up server and wants to delete the backups. Another one to easily switch to a different backend or copy data between them.

This is one of my favorite open source projects, I use it all the time.