After sixty eight posts and no one mentioned the wear and tear on the equipment.
Moving parts can let water in more than a bicycle that is just getting rained on. I was on two bike tours this year where we had one full day of rain each tour. After taking apart my hubs the ball bearings were in a brown rusty grease that pitted one of my cones. Shimano does not have any extra stock of that particular cone, and I have to wait 4 months until the back order is filled.
Flat tires on one tour increased so dramatically the support people ran out of tubes. Wet tires tend to keep objects stuck to them longer and tires tend to puncture more often in wet conditions. Changing a tire in the pouring rain is not a fun task.
Wear and tear alone is not enough to keep me from riding in the rain, but I would be lying if it did not influence my thought process. Higher wear and tear on parts is something you will have to deal with when riding in the rain and should be discussed as well as clothing.