Yes, seeing a red dot dancing on your chest is scary. Hollywood has made them famous and then the tacticool crowd just had to have them. Lasers are one of the most useless overrated pieces of hardware out there. There's also legal ramification too if you do shoot someone with a gun that has a laser. It can and will be played against you in court. Same goes for reloaded ammo, specialty ammo, other tacticool goodies and so on. Understand that this isn't me talking Piob, this is from my attorney who specializes in firearm incidents. He'll also tell you that it doesn't make sense but that's how it goes in court.
You're also wrong about which round is most likely going to over penetrate. Your 40 is more likely going to pass through more barriers and out into the street than a "typical" 5.56. That's just physics at work.
My state has very strong defense of castle laws and the prosecutor in my jurisdiction is very gun friendly. In order for something to end up in court you have to first be indicted.
I'm sort of puzzled though as to how a .40 caliber hollow point will penetrate more barriers than a .223 rifle bullet. Never claimed to be a gun expert so willing to be schooled on this.