If you do not earn, where will you even see the money to gamble? If your weekly income is not enough, that means it is foolishness that will make such a person to gamble. But if you are able to earn enough and safe and able to use like 1 to 5% of your weekly income to gamble without affecting you and your family financially, that is wise.
If you are talking about who doesn't earn steady, but how does such person have money to gamble? I think many people gamble without having a steady stream of income because I have seen several people who don't have a steady job that brings money to them on frequent basis, but they make their money by chance or when they call them for job. For example some professional job that you'll go and work after which you can stay up to 3 months before they can call you for another job. This set of people will still continue playing gamble even with any fund that comes their way. Like taking their wife funds, selling property to play gamble, taking loan to play gamble, deceiving people to get fund to play gamble, Lastly pesting around people who always gamble, for the purpose of leuring them to suit your wish of playing gamble. otherwise know as parasitic Gamblers. So there are many ways I see people who don't have steady means of income usually survive in playing gamble. So there should be need to for people to have genuine means of steady income for the sole porpos of not embarassing yourself with people or doing some things that is not reasonable.