Your ad exec is about the equivalent of me discussing new libraries / languages / frameworks out of work hours. I never heard anyone ask for that in an interview. I have seen a fair amount of ads asking to see my side projects / github.

I am reluctantly creating a side project at the moment, as I want to get into freelancing, and all my previous work is in house. Even without kids I find it difficult to find enough hours to put into it (trying to use a free hour here and there leads to almost zero productivity, I need a minimum of three at a time).