We wouldn't keep doing it if it sucked.
I actually like commuting more than any other kind of riding. It gives me about 10 times more purpose than any other kind of riding.
A carradice is actually probably the most ideal bike bag for commuting unless you need to carry a laptop. It is usually just enough space, is the least weight compared to a rack+even just one pannier, and is easily transferable between most types of bikes. I wish I had chosen a carradice style bag for my bike bag.