Regarding measurement, lasers are useful vs. standard light because lasers can have a specific wavelength or very tight wavelength range. You can then build a reciever that is only looking for THAT specific wavelength/s (either direct or from a reflection).

Also the light from lasers is directional, meaning the light is all directed in the same orientation, hence why lasers are a beam and not diffuse like a flashlight

Lasers can also be used in safety systems (and standard systems) as a "plane" that when broken (meaning something has passed into the beam of the laser, disrupting its unaltered flow to the reciever), it triggers something (like a shutdown, an arm to pick up the object, etc.