Some people who keep their gambling a secret, in my opinion, are people who don't want to take risks, because I myself do it like that, I don't want anything that could trigger conflict with the gambling I do. Therefore, keeping the gambling you do a secret, including the winnings you get, is good.
Keeping your gambling habit equals not wanting to take risks? Not necessarily so. People who keep their gambling habits a secrets perhaps don’t want their affairs out and about in the public. Risks has nothing to do with keeping your affairs private as you could always and at anytime, take same huge risks privately as others publicly do without anyone knowing about it.
I’m a big fan of keeping your affairs private, only sharing to those friends and family close enough and who deserve to have certain information about your activities.