Personally, I think it is faster to to point the red dot at something then to line up a target using sights but that is just a guess.
Hey, Space. That it not necessarily true. There are plenty of videos, discussion, opinions, and what not on the subject. It basically, as stated by others, comes down to training. Most people will spend significantly more time searching the target for the laser dot, rather than if they used iron sights. This is especially true in lighted conditions.
Now a dark room, well...you still have to "see" your target to light them up with the laser. The light/laser combo is good for that.
Also, laser dots grow with distance. Only in the movies is the red dot teenie-tiny 200 yards away.
Red dot sights/optics take getting used to as well. Depending on the size of the dot (small MOA versus big MOA), it could take longer to search for the dot. Once again, training can help with that.
The general thought with any handgun is that it's for close quarters. Not too many people want to get into a fire fight with a pistol at a 100 yards. With that said, iron sights, lasers, and red dots just need to get you onto the center of mass of your target. When the proverbial poop hits the fan, no one is going to take a long time to line up the perfect shot.
So...train for your intended use. If home protection in low light...train that way. Get used to that laser. It should be automatic to engage the laser (pressure switch or finger switch).
Now, dry fire doesn't necessarily mean "pulling the trigger". It also refers to drawing for holster, bringing the firearm up from a ready position to the target, grip control, safety manipulation, mag change, etc and so forth. I like to practice drawing and lining up my sights (with finger not on trigger). There are tons of exercises out there. Ay exercise that doesn't involve live fire. [#1 rule: make sure firearm is not loaded, #2 rule: see #1, #3 rule: use a wall or barrier that you don't mind putting a hole in, in case you missed rule #1]
With all that said (the rambling parts)... a good drill indoors may be to cast very low light onto a simulated target in a dark room, and practice acquiring the target with the laser. See Rule #1!!!!
These are just my thoughts/opinions. Mileage may vary.