Lasers unlike red dot sights put a naked eye visible dot on to the target. They are very good for reflex shooting "from the hip" at close quarters, ideal for vermin in barns, birds on branches.
Important note is that red lasers are only of use in low light or dark. They do not work well in daylight.
Always keep safety in mind when using lasers even weaker red ones, never shine into the eyes of a person or animal
Note - Scope tube mounting models will not fit compact scopes, there is simply not enough room on the tubes. The only solution is either a side rail mount or mounts with tactical tops to which ones of the rail mount models can be fitted.