We are of the philosophy that a gift is not a gift if you expect something in return. Taking care of your clients is the aim, it just so happens that their response is a positively massive side effect.
While it is uncommon for your clients to respond, it doesn't necessarily mean they aren't talking about it with their friends, family, and colleagues.
We also want to consider the amount of response you've received from traditional prospecting or client experience channels, probably slim to none. In this situation, you've taken care of your people who have given your their trust and their business.