Entertainment is the correct reply in my sense. People are different I know that. Someone definitely think that making donations are much better and worthyer. But I'm not that type. I gamble to spend my free time on a nice wave, to take a risk and have some fun. To gain some profit from that also would be nice 
There was a thread posted in this subtopic awhile ago asking on what matters whenever you gamble, either the process or the outcome. Most people have replied that the process is what makes gambling attractive, while the others replied the outcome of their decision.
Like what you have said, it varies per person on what they see and feel towards gambling. Some people who are financially struggling tend to look gambling as an avenue of gaining them quick profits, while people who are financially secured see this as a form of entertainment. Regardless, gambling will always be something that people would spend their time and find meaning to it.