The reason for disabling SMS sending is that the company improves the security of user accounts, since the technology used for sending SMS shows some vulnerabilities. Users will still have access to any important messages they have saved on their mobile phone, as well as messages containing information about the account.
In Spain, and in most of the world, this function is little used, since for most users, sending SMS from Twitter is relegated to the authentication functions of the platform. However, the possibility of receiving SMS notifications could be useful if, during an internet blackout, the user wanted to continue receiving information from official accounts, as happened during the blackout in the Indian occupied Kashmir.
It should be remembered that, in September of last year, Twitter already disabled the possibility of sending tweets through SMS messages in almost all the world. At that time, the decision was made as a result of a security problem suffered by Jack Dorsey, the CEO of Twitter, who was hacked into the phone through the function of sending tweets via SMS. The service was never restored again and now the SMS are unusable for Twitter after also deactivating the sending of notifications, as reported by Twitter in its official support account.
We’ll reactivate this in markets that depend on SMS for reliable communication soon while we work on our longer-term strategy for this feature.— Twitter Support (@TwitterSupport) September 4, 2019
Twitter was originally created as a communication service intended to be used via SMS, hence, from its launch until 2017, Twitter has only allowed tweets of 140 characters and is also one of the main reasons that Jack Dorsey uses to ensure that the Message editing, so requested by users, may never reach the platform.