In my country (Nigeria) there are many gamblers who don't have savings and it isn't help matters at all. Most of these gamblers can't afford for there families but they can afford money they will use to gamble. So why are they not having savings that they can use to help there families in time of lack. Like they said, we save money so money can save us tomorrow. But these gamblers doesn't know that.
The simplest and shortest answer is due to their addiction. Instead of feeding and meeting their obligations, they would rather choose the selfish route of personally satisfying their greed for their addiction in gambling. This definitely also affects ultimately their savings and emergency money, which is also the reason on why majority of gamblers are high on debt.
If you know someone who is a gambler, then now is the time to at least educate and support them in solving their addiction in this dangerous habit. Not only are they slowly destroying their lives, but they are also affecting the people around them.
Addiction is indeed the main cause because if you are that someone who does have a good control of your emotion and does have good money management then you would not risk out your savings just to play gambling.
Everything would be in control which is a must.