Why is the SMS mass market always just needed?

This question is too in place, hahaha, why? Because the distance between mobile phones and people is too close, the binding force is too high. There is a limit to the number of major app installers, but there is no such limit for SMS. Moreover, SMS can send information directly without the consent of the other party and without opening any software. The difference between SMS and telephone is that SMS is sent to the mobile phone and recorded, which will not take up the time of the marketing staff immediately, and can be viewed at any time, and generally the whole content will be viewed. Even if I want to delete it, I will delete it after reading it. That's the truth. Ha ha ha. And now all kinds of verification codes and retrieval codes have to reach the mobile phone, which is closely related to personal life, so it is just necessary to call it by SMS.