On a side note : are there still people using sms?
Now I see you don't really understand the Different between A2P SMS and P2P SMS. Birdchain offer A2P that's application to person SMS. Your SMS plan normally comes sometime unlimited but you turn not to used the SMS due to whatapp, telegram and many other new instant messaging App. But Birdchain offer you an option where you can now sell those your SMS to companies who need the SMS to reach out to their client.
When you login into your bank, you receive an SMS code which is an extra layer of security. That sms you receive is A2P sms and is been provided by a third party to your bank or the crypto exchange you are using. Also Business used SMS to reachout directly to their client since it is a very reliable means to reach client with very high success rate. There are many used for A2P SMS.
You can read more on Birchain whitepaper below.
https://github.com/Birdchain/whitepaper-business/blob/master/README.md