I believe that beggars don't gamble for fun. So do you think that it's because they feel that they don't have anything to loose and somebody will still give them money if they lose? How will you feel if you see a beggar that you just gave your hard earned money using it to gamble?
Now we know why they are still beggars, they are so addicted to easily made money which they did not work hard for. There is no reason that is enough to justify beggars for gambling. A beggar who gambles is a lazy and irresponsible. Since their major aim of gambling is to make money, there are chances that they will be investing all the money they are making from begging into gambling. It becomes even worse if they are losing so much and chasing losses. Begging to sustain their gambling desires is the most miserable lifestyle I can imagine right now.
The dangerous thing is that if a beggar is already addicted to gambling, he becomes ambitious to continue gambling and is very passionate, he will certainly commit crimes to get anything in order to get money to gamble, not a few people commit criminal acts to get money to finance his gambling.
The poor are not fit to gamble when it comes to morals and logic especially for someone who understands finance, and the beggar makes money by gambling, it will not find a decent thought for a person to do gambling when he does not know what he will eat tomorrow.