No, there is no safe method in gambling, if there is one the payout must be really low so it is not worth enough to try it. It is not safe method to earn fast money because there is no way you could win like fast money without risking anything
Yes it is true and it is pretty safe but you need really big bankroll to get more balance, so most people is trying to play through gambling rather than investing because with gambling you can earn more and faster rather than stay investing all the time. May be you can invest if you have spare money but you need a lot of bankroll to see the result