The SMS/ Text message feature is very useful, but the current implementation is very rudimentary. Modern messaging applications found on any mobile device, or apps such as WhatsApp, iMessage and even Google Chat have the option to react/ like a person's message. This is useful when you want to acknowledge that you received a message without actually sending a message back.
Please see the implementation in any modern messaging app. You receive a message from someone. You can click on the message to add a reaction (heart, thumbs up, or other emoji, etc). This currently cannot be done in either the RingCentral Web/ Desktop App, or Mobile App.