The proliferation of mobile devices also adds to its allure. Entering lengthy passwords on smartphones isn't very practical when calling to get access to bank account balances, for example.

移动设备的普及同样增加了这种技术的魅力，举例来说，当人们打电话查询银行账户余额时，在智能手机上输入冗长的密码并不是很方便。