Installers can easily take pictures and attach them to the job. One use for this is when a customer tries to make a claim against your work. If you have the photo evidence, you can use it prove you did the job the way you were supposed to, even years after the fact.
Why is this important? Taking photos of your work can be invaluable, but having to keep track of those photos becomes a pain. Using this feature, you can keep your photos next to the job that they were taken for and know that you have those saved where you can find them again if you need to.