From a tactical standpoint, the extra length and weight of a "silencer" and the consequent decrease in mobility of the firearm would more than negate any benefits of having one. I'll take a gun that I can draw and maneuver quickly over a quieter gun in any probable situation.
I think if one needs to defend against a potentially deadly threat, considerations such as possible hearing damage take a seat very far back in the bus.
There has got to be a few people out here that have a suppressor for their handgun.
If you're involved in a self defense shooting a can is an essential safety precaution.