I'm curious as to their usefulness, particularly at close range home defense, and you were talking about how basic self defense courses are going to train you to look down the sights. Are they really necessary, or is it a cash cow market? And is someone that has taken a basic self defense course typically someone that has the mental fortitude to aim their pistol properly with these?
Assuming a shoulder width of 2 feet, with the maximum distance of 10 feet (since you specified most encounters will occur at less than 10 feet away), you'll have roughly a 12 degree horizontal range to still hit your target. If someone has taken a self defense course (which would provide the training for the use of night sights) and trained in the use of a pistol, would they still suffer a 6 degree shift in accuracy? If the light is so bad that you need the night sights in order to prevent a 6 degree shift in horizontal accuracy, wouldn't you have problems identifying the intruder period?
I was thinking about one thing, as you commented that there are zero cons to night sights. Wouldn't they also provide an opportunity for the intruder to spot you before you spotted them? I can't imagine it's a safe assumption that you'll always spot them before they spot you.
EDIT: Changed "questioning" to "curious" in the first statement.