Facebook doesn’t store or save any of your SMS conversations on its servers. However, you get to use all those stickers, emojis, and location-sharing features native to Messenger with your SMS chats.
Why does this matter? Some other messaging clients often don’t include an option to send SMS messages. SMS Text messages are a popular way to contact people. They don’t require contacts to use the same app or service as you. Messenger solved this pretty well when they added the SMS service, a worthwhile option to stay in touch. The Ultimate answer for anyone that uses both Messenger and needs to SMS text, other people. Users have the best of both services in one application.