After much searching and trying to solve the problem, I decided that it is necessary to propose the idea.
In one of the projects I use Data-Driven Behavior at some point, I need to get the default response if no suitable match in excel file.
I also have a reply from support regarding this point:
It is by design because the response body is the template filled in by the values from the dataset. There is nowhere to specify a fallback/default.
I hope, I not the only person who could help implementation of this idea.