How safe ? In terms of earnings, its a 50/50 probability of wins and losses it all depends on luck. With regards to the security on the gambling site, there are many sites who scams desprate gambler so you should be careful on that. Gamble only to those recognized sites. You cannot make a living depending only on gambling. Its like betting your 3x a day food everyday, well, if thats okay with you then go.
In short, we come to the conclusion that gambling is not safe at all. it is never a win-win situation in gambling, you are always at the verge of losing whatever you have bet in the house. The win-win circumstances are only for the house who is controlling all.
Of course, it would not consider as a win-win situation but at least the chances are the same. So you should be careful of playing and do not let the emotion controls you. If you are a professional gambler, you will know how to deal with it. It is just a matter of skills and some luck that will bring you to the throne of winning.