Having fun on gambling will lead may lead you into an addict. Ofcourse youre playing money it has an possiblity that you can become an addict to gambling. The intention of having fun may lead you to play because of money and become an addict. But it is all depends on the player on how they will respond to the situation.
I do not believe having fun will lead you to an addict, but rather you will be able to control yourself the more. In fact, it is either you are seeing gambling as fun or you are seeing gambling as a way to make some money by getting lucky and the last time i checked, the latter will always make it easy for anyone to become an addict than the former.
However, if all I want to go do in a casino is just to have some fun without having the mindset that winning is a must, then I would be able to know when to stop once I have exhausted my budget for gambling and if I am lucky to win anything big, I will simply just be happy, take my winning and go home. Too much of everything is always bad anyway.