wondering alex.. let's say a hyperthetical that your in an accident.. and the other guys at fault.. he's wrote your car off but he's not insured at all..
if you was on full comp insurance.. they'll fix/replace your car at a "not at fault" claim, costing no excess at all and the insurance company will chase him down for the money. where as if you had to chase him it could be ages before you get money and that's if you don't get the run around (had this happen to my parents, and cops eventually said not worth chasing anymore)..
Insurance has it's perks, but also it's downside..