Using a statechart increases the number of lines of code
When you solve a problem using a statechart, it forces a certain structure upon the code. For example, since the events should no longer directly cause side effects, the events and those side effects (called actions) might need function signatures, and simply be more “explicit”.
This forced structure can increase the number of lines of code somewhat, but the resulting code generally has a lower level of complexity, meaning that it becomes easier to reason about.
This difference, however is most visible in smaller codebases, where one could argue that statecharts are overkill. However, as time passes and the smaller codebase grows, a statechart based codebase will generally not grow as rapidly as that of a codebase employing a traditional solution.