Advantages of Litestream over https://sqlite.org/rsync.html ?
So I would treat sqlite3_rsync as more of a demo than a stable product right now.
Litestream provides near-real-time offsite replication and point in time recovery, which sqlite3_rsync won't do on its own. You could probably build a litestream-like product based on sqlite3_rsync but it probably won't be as fast or as efficient on storage.
I would probably run both litestream and full backups, to get extra safety
The advantage of sqlite3_rsync is that, if on the other end is an SSH server with sqlite3_rsync, you only transfer the changed pages, and still get a “perfect” copy of the file on the other end.
The advantage of Litestream is that on the other end does not need to live a “server,” and still only changes are uploaded. If you do it continuously, you get many points to recover from, and many of those cross reference each other, saving storage space too. On the flip side, you need the tool to restore.