Threat -for you if you treat Gambling as a Source of Income to earn more quick Money and also if you become addicted to gambling because you could lose all the money you have and also this will ruined your life because you can't control your self to gamble.
I believe almost 80 percent of gambling community is either addicted or use it as an earning source. I do know few firends of mine who have been utilising most of their salary to feed their addiction.
Fun- is when you treat Gambling as a time wasting and for fun only, If you have control to your self and know your limitations .
I use is it to pass time and I am not gambling everyday as I am too pre occupied with my work. I believe you can also if you choose to work more than sit and gamble.