The usefulness really depends on the team. If you're working with another engineer or two and they're all senior engineers that you've coded with for a while, t

The usefulness really depends on the team. If you're working with another engineer or two and they're all senior engineers that you've coded with for a while, then it's probably not necessary since you'll understand each other. However, if you work with a junior team or you have to inherit a project, then I've found static typing to be extremely useful. One might argue that code review is suppose to solve for that, and while you can catch some of the problems, you won't catch all. It's definitely helped to make refactoring faster. Specs will help to some degree, but static typing will traverse through every function to ensure the parameter you're passing is as expected. No more is this suppose to be a nil, a blank value? You can specifically define what you expect. While some people hate optionals with Swift, I've found it to be an interesting concept.