I live in Maine which is a Castle Doctrine state and has a stand-your-ground law. But I have heard from a few people saying that it's not a good idea to have a laser due to the fact that "you know exactly where your round is going and if lethal forced is used it was intended for that reason". And in return could back fire in court.
If in your state the statutes on use-of-force support the use of deadly force, then the use of a firearm in defense of your life in such circumstances is justifiable and supported by the law.
Seems clear to me that any tool which helps you reduce risk of failures of accuracy is a solid improvement in safety for bystanders, reducing the chance for rounds to miss the target. Hard to argue that's a bad thing.
Of course, anything that increases the effectiveness of any deadly force you do happen to be forced to employ
could be argued to be a bad thing I suppose. But IMO the law's on your side if such things are on the books.
Personally, I myself wouldn't worry about it. Presume that
any attack against your life which you defend with deadly force is likely to be vigorously rejected by those seeking to "close the case" and go after the person left standing, if only because that person's left standing. Not because you were wrong in your actions.
If still concerned, speak with a competent and successful attorney regarding the justifiability of such actions in self-defense cases.
Ditto on the training suggestion. It'll be far more useful to you, in the long run. And you might even find a laser isn't a cure-all for poor marksmanship.