Benefits of mobile sub card: the mobile sub card can share the traffic in the package, so if you can't use up the traffic, you can use it for the mobile sub card. There is no charge for mobile main and auxiliary cartoon calls, and there is no limit on the length of call time.
The advantage of the mobile sub card lies in the sharing of talk time. For example, if the package sends 300 minutes of talk time, you and the mobile sub card can use the 300 minutes. The advantage of mobile sub card is that it does not include other monthly fees, so if your family needs calls and traffic, it will save money.
Disadvantages of the mobile sub card: the mobile sub card may cause the signal of the main card to deteriorate, and the main card can query the call records of the sub card. (YiDongFuKaDeHaoChuYuHuaiChu)