I think it is a fair question to ask. A lot of people are using tablets to do some, but not all, of the things that they used to do on a desktop or laptop. If you are in the market, I can see why one would wonder how much use other folks get from their iPad vs Mac, since it might influence your buying and refresh decisions.
For work, my employer provides a laptop and that's pretty much what I use.
For home, I own a Mac Mini and iPad. They complement each other nicely. At least 80% of what I do at home is done on the iPad. It is just so convenient for email, calendar, web, photos, books, etc.. The Apps are great. I also do simple content creation on the iPad using iWork and Notes. If the content is more complicated, which is rare, I will polish off the draft documents on the Mac Mini. Frankly, when I come home from work, the last thing I want to do is dive into complex spreadsheets and presentation......I do that all day long at work. So, the iPad's simplicity and ease of use is ideal for most of what I do after work.