In the aggregate, almost no programmer can think up code faster than they can type it in. But being a better typist still helps, because it cuts down on the amount you have to hold in your head.
Similar for automatically generating boilerplate.
> If I don't know, how can I trust the generated code to be correct?
Ask the AI for a proof of correctness. (And I'm only half-joking here.)
In languages like Rust the compiler gives you a lot of help in getting concurrency right, but you still have to write the code. If the Rust compiler approves of some code (AI generated or artisanally crafted), you are already pretty far along in concurrency right.
A great mind can take a complex problem and come up with a simple solution that's easy to understand and obviously correct. AI isn't quite there yet, but getting better all the time.