I think it's basically mostly because the Tarsnap tooling has a very principled design, is reasonably easy to use for power users with basic use cases, and perh

I think it's basically mostly because the Tarsnap tooling has a very principled design, is reasonably easy to use for power users with basic use cases, and perhaps most of all because the operator of the service (Colin Percival) is a tremendously well respected figure in the cryptography world. I describe the tarsnap tool as being "principled" because it draws a pretty tight boundary of what functionality is in-scope. As a result, I think most real "backup" scenarios will require some kind of tooling to be used as a wrapper (e.g. GFS or even simpler retention scheduling). I was a Tarsnap user for some time, but in the end I've found that using Duplicati with B2 is actually easier than Tarsnapper and significantly less expensive, as my usage totals a bit over 7TB - not affordable for me with Tarsnap. As a result I haven't been recommending Tarsnap for some time. I do think it's important to emphasize that "B2" or "S3" does not necessarily mean doing scripting or whatever yourself - probably the biggest advantage of choosing one of these commodity storage services is that they are supported by a wide variety of open-source and commercial tools, generally with much a much more sophisticated featureset than the tarnsap tool. Duplicati as mentioned is a more GUI-centric (web interface) tool with block dedup and retention management for .NET/Mono. "rclone" is a command-line tool for Linux that's fairly similar in usage to the tarsnap tool but also has additional features. Both can be set to encrypt backups before uploading. Both support either S3 or B2 (and I assume also Google Cloud Storage, Azure Storage, etc).