The reflection off of the screen tends to bounce back almost as straight as it hit, where as a standard beam of light radiates more on the reflection.
My home theater which is about the same as a Movie theater with regard to the seat placement that is fine. You can't get to a spot in the room where you'd be at a 45 degree angle. But in many people's homes, or for outdoor projection in commercial settings it can be an issue.
Laser is also nice because you don't have to deal with focus. The Focus is fixed.
Where you do have issues with Lasers is color. Lasers are harder to get to match the Gamut, and harder still to manipulate to represent all the colors in 10 bit color, (10 bits x 4)
Lasers don't tend to burn out which is nice.
Laser projectors do have to be optimized for the size of the screen more than projection. With traditional projection the size of the pixel scales up. With Lasers the dot doesn't really get larger. This is fine if the projected dot is the right size, or some ratio of the right size.
Say a laser projects a dot, a pixel sort of, that is 1mm in size at a distance of 15 feet. at 1080p you would have no space between the dots if the projection was roughly 2 meters across.
Now you want to project something to the size of 4 meters across. With traditional projection you change the focal length or move the projector back and the dots get bigger. With a laser you have to put 4 dots (2x2) to do this.
If you want a dot that is only 1.4 times the size you have to use 4 dots and over lap them.
The better Laser Projectors due this. They use up to 9 dots (3x3) and to where each Dot may only be 4 bits, using 9 dots you can fake more colors (3 red, 3 green 3 blue). Cheaper projectors use a technique similar to sub pixels and may use a Line rather than a dot (more like a Dash) for Red, and will have 7 dots 1 Red that is 3x the size, 3 Green, 3 blue.
In any case you have to have enough control over the laser to do the adjustments or you end up with gaps in the dots which are noticeable far more than the space between pixels that show up in DLP and LCD projectors.