I think that async support for multi-read(and write) are part of the reason for the separate Turso library in Rust over the C fork (libSQL). I also wouldn't be surprised if baking in better support for replication was a design goal as well. Being file-format compatible with SQLite is really useful as well.
In the end, the company is a distributed DBaaS provider using a SQLite interface to do so... this furthers that goal... being SQLite compatible in terms of final file structure just eases backup/recovery and duplication options.
I think being able to self-host either in an open/free and commercial/paid setting is also going to be important to potential users and customers... I'm not going to comment on the marketing spin, as it is definitely that.
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.
In the end, the company is a distributed DBaaS provider using a SQLite interface to do so... this furthers that goal... being SQLite compatible in terms of final file structure just eases backup/recovery and duplication options.
I think being able to self-host either in an open/free and commercial/paid setting is also going to be important to potential users and customers... I'm not going to comment on the marketing spin, as it is definitely that.