You could, of course, just download a Julia distribution, fire up the interpreter and see for yourself. But I'm sure unfounded snark is much, much better.
If you want to know the catch, it is that it has high latency at first run, and requires a full compiler at runtime. It is optimized for numerical work, where the long runtime make slow startup irrelevant and low latency is easily amortized.
But if you are suspicious, there are introspection utilities that let you see the generated native code. Give it a try.