I'm considering making a payment, but I'm unsure whether to use Hong Kong dollars (HKD) or US dollars (USD). Can you help me understand the pros and cons of each option? What factors should I take into account, such as exchange rates, transaction fees, and potential volatility? Additionally, how might my choice impact my overall financial position and future investments? Ultimately, I want to make an informed decision that aligns with my financial goals and preferences. Can you guide me through this process?