Reason 1, less people fish for them.
Reason 2, they are hard to catch.
Reason 3, when its -15, everything is covered in snow, its dead quiet and your freezing, a bar of chrome warms you up and puts a smile on your face.
They are easy to catch, tough to find, and they are the most rewarding fish. They bite everything at some time or another, and nothing at all some days. You could say they have personalities. The ultimate game fish.
I like being alone when I'm fishing... and cold, wet, winter days keeps it that way.