When the roads are wet, oil floats to the top of the water. Consequently, fenderless bikes spray you with both water and dirty oil, which results in a black strip down the back of whatever you are wearing. This is bad if it is a cycling jersey. It is worse if it is a $1,000 suit.
The road spray from fenderless bikes also can carry sand, grit, and salt, especially in the winter. This can easily wear out a chain in a few months. It can have similar results with the bottom bracket and other moving parts of the bike.
Last winter, one of my routes had big blocks of ice. Studded tires kept me upright, but I went wham! wham! wham! the whole way. I actually think suspension might have helped.
Paul