That's quite a lot more than not seeing anything. Could be useful if your goal is to determine the number and type of occupants in the room before entering it. I could imagine all kinds of mischief bringers being interested in this.
As a bonus, if your keyhole is wide enough, I guess you could image static objects by moving the laser around.
Or you can just jam a borescope through the keyhole and see things that way. I don’t think peeping through a keyhole into a room was a hard thing even before this.
As a bonus, if your keyhole is wide enough, I guess you could image static objects by moving the laser around.