Yep, everyone has their own situation. We all get to make our own choices. I guess to elaborate on why I think lights are useful, even for defenders in a home with a good castle doctrine law, I'll elaborate.
A defender would still need to meet the requirements for deadly force in SC, even in the home:
1) No fault in bringing about the harm. Probably not an issue in the home.
2 & 3) Subjective and objective belief of imminent danger of death or serious bodily injury... You as the defender get a presumption that someone who forcibly enters your home caused you such reasonable fear of death/SBI.
4) Duty to retreat if you can do so in safety, waived in the home.
Presumptions can be overcome with evidence. They are not iron-clad get outof jail free cards. It is good from a legal point of view to be able to identify the target and articulate why it posed an imminent threat, so that if the prosecutor attacks the castle doctrine presumption in your favor, you still have a leg to stand on. Moreover, the castle doctrine no longer helps once the conflict is outside your dwelling (or porch). What happens if the fight occurs in the driveway or extends out into the back yard? The moment the encounter is off the porch (like: a suspicious figure creeping in the bushes) you need to be able to articulate why someone would reasonably believe that the target posed an imminent threat, which is hard to do in darkness. Finally, the Castle Doctrine doesn't apply if the intruder is a LEO and you had reasonable cause to know that... If you couldn't see the badge and "POLICE" tapes because you don't have a light, then that's likely on you.
From a moral point of view, what happens if the "intruder" is a mentally ill 12 year old who wandered off away from home and poses no imminent threat? What if the intruder is a neighbor who is fleeing a DV situation in a panic? You may be able to legally shoot those folks in your home but there's a moral dimension as well that requires target identification if it can be done in a sound manner.
We all get to make our own choices and live with the consequences, though. Even if you choose not to use the light in most situations it is really, really nice to have it available for some of the cases like identifying someone skulking outside the dwelling. There are a couple of ways to skin the target ID cat (like flood lights for your yard or something) but a weapon light is one of the simpler and cheaper options.
I also like bright lights because they can be used to escalate force and deter situations WITHOUT shooting or brandishing. I've had several times where simply shining a bright surefire at someone approaching me in a sketchy manner at night caused the person to go somewhere else rapidly. I'm not saying that is option A in the home, but it would be nice to illuminate a suspicious sound in the back yard before double tapping the rustling in the bushes.