It can catch all kinds of bugs, but you have to ask the correct questions. So it comes down to define what a bug is and the assumptions you use for testing. And

It can catch all kinds of bugs, but you have to ask the correct questions. So it comes down to define what a bug is and the assumptions you use for testing. And therein lies the problem: what constitutes a bug? A function that add two numbers but bever terminates might be considered bugfree if forget to include as a bug that not giving an answer before the end of the universe is faulty behaviour. We humans are terrible at writing these kind of specifications, so formal verification as a method just pushes the correctness from code to specification.