I think there are almost the same, but it is also depend on how people interpret the two. Sometimes it looks like the same because in trading you will also consuming your effort and time like also gambling. But in gambling you will lose money, effort and time. So I just think it is just depend on how people interpret it.
I think you only spend less effort in gambling but it is more risky than trading, if you are good in gambling then even in just an hour you can already make thousands of dollars, but that is hard to do and only those extremely talented person can do it.