Much to my surprise, purchased actions for Photoshop are popular. An action is a recorded set of steps taken on an object. If I were to start recording, adjust an image for white balance and then stop recording, I could than apply that same adjustment on a set of images by applying the action I had just created to all of the files. Actions can be recorded for all sorts of things done in Photoshop. I can even edit actions, breaking them into sub-sets, changing the order of the steps or adding them to other actions.
Actions are convenient, fast, easy, results oriented, and a few other buzzwords. If I were to purchase an action, I'd be able to apply it without needing to learn much about how Photoshop works. I would only need to know how to install and apply an action. While I clearly see the advantages of using actions, I also see disadvantages. If I am relying on actions instead of learning how to use Photoshop, I will always rely on actions. For me, purchased actions are a crutch that I don't want to use. As a former rehab therapist, I do not see crutches as bad things. But if I have a choice, I'd prefer not to need them.