Categorising / knowing yourself is important for sure - I think in the case of the extrovert/introvert thing, it's an important first step to helping yourself, because in my experience/anecdotally, a lot of introverts know they're different from others, yet feel insecure or anxious about it. Awareness and acceptance won't make you "not an introvert" suddenly, but it can help recover from the awkwardness, self-doubt and anxiety. Still anecdotally, me and some other people who (10, 15 years ago or so) learned about introversion found more peace with themselves, that it's OK to want to be home, and that they learn to say "no" or "you know something, I've had enough and am going home".

Learning about who you are helps you know your limits and boundaries, which means you can learn to do more within your comfort zone and how far you can stretch it, which means your comfort zone expands and you can do more. That's the kind of growth I think comes with categorising oneself.