You're only file format compatible if you don't use any of the Turso extensions.
Just like STRICT tables, as soon as you use an unsupported feature in your schema, your database becomes incompatible.
With STRICT tables you needed to upgrade SQLite tools.
But if you use something from Turso you're placing yourself outside the ecosystem: the SQLite CLI no longer works, Litestream doesn't work, sqlite_rsync doesn't work, recovery tools don't work, SQLite UIs don't work.
Turso has no qualms with splitting the ecosystem. They consider themselves the next evolution of SQLite. The question is do you want to be part of it?
Maybe. I don't think having parallel divergence is inherently bad. DuckDB doesn't replace SQLite...
But depending on the need, I'm probably more inclined to reach for something like Turso today than Firebird of I want something I can embed and connect to a server to sync against, for example.
Just like STRICT tables, as soon as you use an unsupported feature in your schema, your database becomes incompatible.
With STRICT tables you needed to upgrade SQLite tools.
But if you use something from Turso you're placing yourself outside the ecosystem: the SQLite CLI no longer works, Litestream doesn't work, sqlite_rsync doesn't work, recovery tools don't work, SQLite UIs don't work.
Turso has no qualms with splitting the ecosystem. They consider themselves the next evolution of SQLite. The question is do you want to be part of it?