I always try to avoid giving any information to social media companies if I can help it. These companies have no one's best interests in mind except their own, and they'll sell out all of your personal data for profit if they have a chance to do so (and many of them have plenty of chances to do so). You've got Facebook, which likely threw the 2016 election in the US, and has stated that they have no problems with taking money to run ads that are demonstrably false, and then you've got Tencent/WeChat, which is widely thought to share personal private information with the Chinese government. So SMS avoids that by only giving information to the phone company. Sure, phone companies can store it, but they haven't been able to successfully monetize it (at least not yet). Although it's my understanding that unlike LTE data, SMS messages aren't encrypted all the way back to the home network, which means that even if I'm roaming in a foreign country, the company that operates the network there would be able to see all of my SMS messages too. Even better, I also use Signal, which gives only metadata, but not message contents, to the Signal Foundation, and not much else to anyone else, except the fact that I sent/received a Signal message at a given date/time.