Lasers have a few special characteristics, so they are used for different reasons.
Sometimes to get well collimated light: think about individual rays. They are not radially pointing at every direction; instead, they are parallel. This allows you to get a small dot, which stays a small dot even if you move your target further away. HOWEVER, not every use case of lasers is because of that property, so you can make the laser light non-collimates as well.
Sometimes to get very narrow wavelength peak at well predictable wavelength. So say you need just 650nm photons, not a mix of anything between 620nm and 680nm even shifting with temperature, like with an LED. And again, sometimes this property is utterly irrelevant.
The third reason to use a semiconductor laser is that it can be turned on/off faster than an LED. For example, 3D time-of-flight sensors may use lasers just to be able to blink them at 50MHz or so. An LED would be limited pretty much at 20MHz. Otherwise than that, LED does well.
Oh, and polarization is another reason. Sometimes it matters. You can use filters to make polarized light from a "normal" light source having random polarization in every angle, but filtering loses light; lasers produce polarized light natively.