If you're working on, say, a huge Java codebase, then a debugger is practically essential because you've got a lot of code to navigate, and you probably want to see what flavour of objects are being passed around and how their state is being updated.

On the other hand, if you're working on, ooh, a Nodejs codebase, you're probably looking at less code, with a debugger that's much slower, and probably more functional code that is operating on data directly. Using a debugger in that case is often slower than just using print statements.