Why do you prompt for verification code when you get coupons in Taobao shopping?

The service has been opened. According to Taobao official website's query, when Taobao purchases and pays, it needs to enter SMS for verification. This is because the SMS authentication service has been opened, which is a higher-level security protection product based on mobile phone binding. When this service is opened, you need to pay 0.6 yuan information fee every month, and you can choose to close it, and you don't need to accept SMS verification when paying.