This maybe the most important code of all. Saying thank-you is never full enough. No matter how grateful a person may be it is difficult to say thank-you with enough intensity. So the code provides a powerful way of indicating appreciation and gratitude.
The existence of this code does not exclude other expressions of gratitude. The code can simply be added to these.

Many codes are requests or demands or even expressions of disapproval. Code 8/22 is the opposite. It expresses gratitude.