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.
If everybody who gambles can have that mindset, then the gambling world will be a better place as each and every one will make it safe for themselves and those who cannot afford to lose anything will just have to stay away.
The thing is with even the 50:50, your chances as a gambler to lose most of the time is high and if I want to put together all that I have gambled, I would not be surprised that totally, I am losing a lot, but as long as you do not have problem with that, it is okay. The only way to play safe when it comes to gambling is to not play more than you can afford to lose, and with that, at least, you would not let emotion take over you or see yourself end up losing everything you have.
If anyone is considering safe as winning all the time, then that kind of mentality on its own is not even safe and that is what has led so many people into making a whole lot of mistakes and they are regretting it till date if they are not too addicted to realize it anyway.