They are easier to modify and improve.
Case in point: I'm driving my company's van and had a tailgator
issue. Now the fix for tailgating is a simple mod, you put a solenoid
on a tap from the transmisssion cooler and run it to the exhaust
manifold. A button gives a momentary solenoid open and a smoke blast
emits from the tailpipe deterring the tailgator.
Catalysts make this a lot less effective.
