I use both, spray cans for applying primer,paint to bodies and other large parts.
Although I havent been using an airbrush for very long ive found it is good for paints that arent available in cans,custom mixed colours,Alclad etc and is also good for applying paint to small parts and doing extensive paint jobs like Chris Thobe's.
60 secs ? Too me that seems like a bit of an exaggeration. Even doing a quick back flush takes a few minutes.
As I mentioned above, I havent been using an airbrush very long.
But I personally Iike break to down the entire airbrush and give it a full clean after each painting session,which for me usually requires about 5 mins.