This question reminds me of an article I read a few years ago. The article was about commercial hospital flooring.
Flooring, janitorial and hospital industries were working together to decide what was the healthiest environment for their patients recovery rooms.
In the past hard surface flooring such as sheet vinyl was the only thought since it could be cleaned down to the surface at a regular schedule. They also came to recognize that as germs and debris ended up on the floor is was easily kicked back up into the air by walking, where it could be inhaled by patients, staff and visitors.
Carpet is softer and more comfortable and tends to make family members stay longer. It is a know fact that having loved ones around improves the healing process.
Also when debris or germs fall on the carpet they tend to stay there until the flooring is cleaned next. This helps promotes a cleaner air quality.
With studies like this I am sure the tide will change much like one year coffee is good for you and the next it is bad.
What I got out of this is, you have to give and take. We can make arguments for both flooring solutions.
I do think we should take into consideration the comfort factor in choosing the best flooring for our space. However with cleaning I think it has more to do with how and how often we clean than with the materials that are installed.
With that said I always ask my clients, who will be using the space. Remember things like kids and pets are also an important factor.