Why sending individual messages one by one?

This feature can be used to solve different issues:

1.  Some carriers might apply some limits in term of the number of contacts you can reach at once. There might be a maximum number set per hour, Day, week etc....
2. Carriers want to limit spammers.  So if you send the same message to many recipients at once in a short period of time, this could be caught as a spam and in some cases your phone’s texting feature might be disabled for some time by your carrier.
3. You want to always keep iMessage turned ON as you do not want to miss any messages sent from your friends through Apple devices (via iMessage).
4. You want to keep iMessage turned ON as you want to use it when possible for your mass texts to Apple devices (via iMessage).
5.  You want to send personalized mass text messages by addressing each recipient with information such as Last name, First Name and/or company

How to use one-by-one sending?