Originally Posted by
DieselDan
You answered your own question in your post. You use the MTB in rain and snow, when debris will stick to your tire and cause punctures.
Good points about the likelihood of flatting when it rains, but don't misinterpret my original post. Before I got my road bike the mtb was my daily ride and that was when I had all the flats. I don't see a lot of rain in any case.
Also, I wouldn't consider 28mm to be a narrow tire.