If synchronous IO is blocking your CPU bound application code, this won't help you. My made up example was not about concurrent writes, and the concurrent reads I mentioned were not my main point. For all I care, you could have 100 different databases or even normal files in this scenario and you read them.
I was wondering how the async wrappers around SQLite work when SQLite itself only has synchronous IO. At least for the Rust example by Op, the async part is only used when awaiting a queue, but the IO itself still has the potential of blocking all your application code while idling.