It will be very bad for someone who chooses gambling as a full-time job because one cannot win consistently by gambling for a long time. And one who gambles for a long time becomes deeply addicted to gambling. And one who chooses gambling as a full time job must gamble at least 8 hours daily as an official time and if he gambles for such a long time he will become deeply addicted and face huge losses. so gambling should never be chosen as a full time job
Gambling is filled with too many uncertainties to be a full time job, infact it's a 50/50 game so making such a job opportunity will be very risky for anyone who tries to because they can't be sure of how much they can make at a particular time or how much they will be loosing aswell so it's better not to think in such direction at all as it's a more risky than profitable.
Gambling for eight hours daily is definitely going to expose such person to too much risk that they will not be able to recover well enough anytime soon, they will definitely get to addiction and they may result to unhealthy habits in the long run after been unable to continually win so as to fund their gambling habit continually. It's always advised that you get a good paying job and let gambling be something you do on the side and not to be seen as a profession because it's filled with uncertainties.