Could be very useful in a low light situation...especially at home. My wife has a Crimson Trace on her S&W M637 revolver for that reason, and the same gun doubles as her CCW...that Crimson Trace does not add any bulk.
As a training aid, lasers are fantastic for trigger control and grip consistency problems. As to seeing the sights and your tartget, at night, at any distance over 6 feet or so, tritium sights or a laser are about the only way you're going to be able to get hits, short of a shotgun. Try it sometime...with or without flashlight in the crossed wrist mode...you'll be a believer. I'd opine that most defensive shooting is done in low light situations...you be the judge. Rod
Our Flag does not fly because the wind blows against it,
It proudly waves because a soldier's dying breath blows upon it.
USAF Forward Air Controller, 5th Spl Forces,
An Loc, lll Corps, RVN, 69-70, Vietnam Vet '69-'73