Query related to naam jap/bhajan

So since im very much inclined towards Advaita Vedanta and the basic principle of them is "aham brahmasmi" then why am I supposed to do naam jap since at the end of the day when i day I'll be one with him, my true nature? This is may seem childish but as a beginner im not understanding the logic. Please anyone learned in Vedanta please shed your light upon my query. Namaste 🙏