Two things are involved. One is, did your husband understand how gambling works or not? The school question is: even if he doesn’t view gambling in a positive manner, if he wishes to start gambling, will he be able to control his emotions and finances? If you get these two answers, you are covered by the case study. This is your husband, so you are expected to know many things about him, which include his reaction to things that he doesn’t like. You will find it easy to know if he likes gambling or not.
For instance, you will have a discussion with both of you about the fact about the fact that you saw a film that was fully focused on gambling and you found out many things from there, so what is his view about gambling? So from here, he will be able to express his feelings about gambling. You don’t tell him that you are the one doing the gambling because if he hates it, he will definitely be angry with you. That is why sometimes you have to use some strategies to ask other people for ideas without their knowing.
You probably didn't read the OP because you have missed the context of the topic. The topic isn't about the wife telling her husband that he should gamble, but it's about the wife telling her husband that she gambles, which means that the wife gambles but the husband doesn't know, and now the wife is asking whether it is good if she tells him about it or not.
In my opinion, it all boils down to the trust thing. You never know what he might think after he comes to know that you have been hiding this from him this whole time, and this might create trust issues between the two, but if you don't tell him and he comes to know from somewhere else or himself, that would be even more heartbreaking because I can't even imagine that my partner would hide something from me and I would come to know about it from someone else.