Embassies ask for travel itineraries primarily to assess the legitimacy and purpose of your trip. By reviewing your plans, they can verify that your activities align with the type of visa you're applying for—be it tourism, business, or something else. It also helps them gauge your financial capability to sustain yourself during your stay, reducing the risk of you becoming a financial burden on the host country. Additionally, knowing your travel plans can assist in evaluating any potential security risks. Overall, it's a due diligence measure to manage who's entering the country.