In the year 2017, there is no reason not to have a light on your handgun. If you use your gun for home defense, it is critical to identify the threat and the backdrop. The easiest way to do that is with a weapon mounted light. You must also be careful not to point your gun at your family as you search.
PS: Keep your hand away from the muzzle as you manipulate the light.
Photo courtesy of Wicked Grips
If I'm in my house I know who is supposed to be there and who isn't. As a family we discussed the fields of fire, no shoot angles, etc. Lights are good but I'd rather not advertise where I am. If I do my job the intruder won't know what hit him.