Smart Message vs Auto Reply

What is the difference between a Smart Message and an Auto Reply? 

Smart message requires an outgoing message to sent and prompt recipients for a yes or no reply. Based on their response, Cadence will automatically send a pre-configured follow up message.

Auto Reply does not require an initial outgoing message and utilizes the matching of customizable keywords. A contact can text into Cadence a keyword and receive a pre-configured auto reply follow up message.

Note: You can choose to compose an outgoing message to prompt a reply of a keyword, but an outgoing message is not required.