> you may as well run MySQL

You're right, there are use-cases where SQLite is not appropriate. But nothing beats the ease of installation/backup/maintenance of SQLite compared to server databases like MySQL or Postgres. Another point is development: For unit-tests, I found that initializing a SQLite database for each test-run is much easier (and faster) than having a VM that runs Postgres/MySQL/etc, which I have to spin up and tear down before/after each test run.

Eh, the backup is a bit of a pain... The sqlite3 tool supports a .backup command but it's basic and can't even write to stdout, only directly to a file. There is an online backup api though but most APIs and libraries built around sqlite don't even acknowledge it, let alone support it. Just copying the sqlite file is of course not a real backup and if done at the wrong time will lead to a corrupted backup.