I have a question about lights mounted on guns. Before I ask it I want to state that I'm not trying to being a troll, wise ass or being condescending, but I'm sure I will still catch some flack for it.
How do you guys feel about the safety rule of not pointing your muzzle towards anything you don't want to destroy?
In my opinion the WML is a supplement to a good handheld, not an alternative. I don't think it's wise to rely solely on a WML. One of the cons is, like you said, the beam is tied to the bore axis. As was mentioned upthread though, most handgun beams have a fair amount of spill and the hotspot is not as narrow as rifle lights. The spill is reasonable for search purposes, and techniques such as umbrella or baseboard lighting with some of the newer lights (like the 1000lumen X300 that's on my guns) will absolutely light up a room.
I know you were just asking out of curiosity, but I would encourage everyone to take some reputable low-light training if your resources permit, it's eye-opening.
Also bear in mind a lot of what you may have SEEN (news, tv, movies, pictures on the internet) that inform your question may be mil/le using lights, and while I have no experience in either of those realms, I get the impression that they have different SOPs/ROEs for their weapons. They are using their lights to search, hunt, control, etc. a lot more often in my estimation. In an occupation where it's (more?) acceptable to hold someone at gunpoint (which, again, I'm ignorant of whether it is or is not acceptable policy), for example, the question you raised loses a bit of the edge.