Thanks for the responses.
Yes, it's lack of imagination on my part. This is because I tend to think majority of other things that I do in my life are easier or faster to do without VC. I'm so focused in making VC to perfectly fit my immediate needs as I initially wondered, that I have no room in the brain to match it to other tasks, like work for example.
Sometime in the future I'll probably want to expand VC usage to other areas of my life, or even creating something for disabled people. The last is actually a very good idea.
So taking into this boat, I think I would try to have both Cortana and VC (which I currently call Doris) hearing me all the time. If that could be possible somehow, I could then ask the tasks respectively to Cortana and Doris according to what is easier for each of them to execute. For example (just thinking, not sure what is actually possible):
Cortana, search web for the future is here.
Doris, read search results.
Doris, new email attach search result 1.
Cortana, someoneone@gmail.com
Doris send the email.
Doris, turn all the lights on.
Cortana, search hard drive for photos named Orlando 2015.
Doris, slideshow current photo search.
etc...